Long before packets of freeze-dried cultures for milk existed, there were dairy ferments. Cheese, yogurt, and kefir are probably second only to beer in the pantheon of fermented foods. However, in the modern world, 100 percent wild fermentation in dairy products is rare. There are many cheeses made from raw milk, though, and the fermentation of these is a joint effort between wild microbes and cultivated bacteria. Cheesemakers who use this approach rely heavily on wild microbes to produce a superior, nuanced cheese, but hedge their bets for optimal acidification and flavor by adding a pinch of commercial cultures. For those who want to play on the wild side, a deeper understanding of the concerns and the process is necessary.
I like to think of the teat surface as a garden from which wonderful microbes can be collected. This collection can’t happen without paradigm shifts away from the extensive udder sanitation that’s practiced on most modern dairies. But wait, didn’t I just warn you about all of the spores floating around? How can reducing sanitation help?
We’ve used lacto-fermentation regularly at Pholia Farm when making our commercial cheeses. I find it amazingly informative to the daily practices of the farm, as well as to my cheese-making. I also employ it during the classes I teach. It’s a method well worth using when making cheeses at home. The practice will help you more deeply understand and troubleshoot fermentation and issues with a mother culture. Making raw milk cheese gives you a chance to observe environmental microbes and natural milk systems at work in cheese-making, and the complex relationship these microbes share with those that exist in a raw milk source.
In this video I go over the intricacies of monitoring pH at different stages of cheesemaking – including what that pH tells you after the cheese is done or partially through aging. I throw in tips and suggestions for how to control acid production in the vat and why it matters! I sure wish it had chosen a frame with my eyes open!
This 24 minute video is useful for cheesemakers at all levels, unless you are brand new to cheesemaking and not quite ready for some deeper science.
It is hard to sort out all the different types and categories of rennet. For that reason, you often hear them mixed up, even by some experts! Here is a little guide that will hopefully help you sort them out – and keep them straight!
Rennet vs. Coagulant
While the term rennet originated from the use of enzymes (formerly called rennin) from the true stomach (the abomasum) of a young ruminant, it is perfectly acceptable these days to use it to refer to any product, compound, or ingredient that is added to milk to produce a slow coagulation (as opposed to adding acid for a fast coagulation). The term coagulant is synonymous.
Vegetarian vs. Vegetable
Vegetable coagulants are truly made from vegetables. Examples include thistle rennet (usually from the cardoon thistle), fig sap, lady’s bedstraw, and several others. All vegetable rennets are vegetarian, but not all vegetarian rennets are made from vegetables. Vegetarian rennets are made two ways, one by the growing and collection of a natural enzyme produced by the microbe rhizor mucor miehei and the other by the fermenting action of microbes that have had the animal gene for producing chymosin spliced into their DNA (genetically modified).
Traditional or Animal Rennet
Animal rennet contains chymosin, the primary enzyme desirable for cheesemaking. Chymosin and pepsin (another enzyme) are both produced in the true stomach (the 4th compartment) of cows, goats, and sheep (other ruminants as well). The younger the animal, the more chymosin is present, compared to pepsin. The best rennet for cheesemaking has over 80% chymosin. The percentage should be guaranteed by the company making the rennet. Comes in single strength liquid or tablet form.
Fermented chymosin involves the use of genetically engineered (or modified) organisms. In this case, microbes are modified to produce chymosin (no pepsin). The microbes produce chymosin through a fermentation process. This type of rennet is microbial, but not all microbial rennets are the product of engineered microbes. Usually sold as “double-strength”.
Most often refers to a coagulant produced naturally (but grown and harvested in a laboratory) by the microbe rhizor mucor miehei. The enzyme produced by this microbe is not chymosin, but acts in a similar fashion. Has an undeserved reputation for causing bitterness. Can be purchased in an organic version. Usually sold as “double-strength”. Available in shelf-stable tablets.
A coagulant made from the true stomach of an adult cow. Mostly comprised of pepsin which will coagulate milk, but is not desired for cheesemaking as it will produce bitterness progressively as the cheese ages.
Who doesn’t love fresh, squeaky cheese curds? Plain, slathered with pesto, deep fried, or with fries and gravy as poutine, cheddar curds are fun and delicious. But making them usually involves half the day, and who has time for that? In this recipe, I have shortened up a few of the steps, the result is tasty, satisfying, and a real crowd pleaser.
If you can, use creamtop, non-homogenized milk for the best results. Pasteurized, homogenized grocery store milk works as well, but the texture of the curds won’t be quite as firm and squeaky.
1 gallon whole milk (goat or cow)
1 cup fresh, cultured buttermilk (if purchased, buy one with the longest expiration date to ensure that the bacteria are still active)
1/4 tsp. double strength (or 1/2 tsp single strength) rennet
Combine milk and buttermilk in a stainless steel pot.
Place on direct heat and warm, stirring constantly to 95 F
Turn off or remove from heat
Add rennet diluted in 2 TB cool non chlorinated water
Let set for 10-15 minutes until just pulling away from the sides or firm when pulled away
Cut into 3/8 to ¼ inch pieces then let rest for 5 minutes
Stir very gently for 5 minutes at 95 F
Begin to increase heat very slowly over 15 minutes to reach 102 F
Pour curds into cloth lined colander and tie in a bundle
Cover and keep curd at 100 F for 10 minutes
Cut slab into two pieces , stack, cover and keep warm, use a plastic bag filled with 100F hot water to help keep th
Turn every 10 minutes until chicken breast texture is achieved (about 1 hour)
Cut slabs into ½ to 1 inch long by ¼ to ½ inch wide pieces.
Place in colander over hot whey and sprinkle with ½ tsp salt. Stir then cover with hot water bag for 5 min. (mellowing)
Repeat salting and mellowing one more time.
The curds are ready to eat as soon as the salting is completed. They can be bagged and stored, but will lose their squeak after a day or so. They can also be frozen and thawed to enjoy later. Yum!
As a person who tends to want to follow rules, it is sad to be reminded that a good portion of food production regulations have little to do with actual food safety, rather they are the result of a ponderous, rigid system that steam rolls forward, sometimes based more on the ease of generalizing rather than the complexity of reality. The FDA has never liked wood shelves, especially when you sit food, in this case naturally rinded cheese, directly on its porous surface. Wood does not fit their Good Manufacturing Practice (GMP) model for a cleanable surface. While wood aging shelves have technically never been okay with the FDA, they have until now been mostly ignored and the decision to allow them been left to individual states .In many” big cheese” states, the regulators defer to the scientific knowledge of the leading expert within each state. For example, in both Oregon and Wisconsin (where at least 30 million pounds of cheese is aged on wood each year) the departments of agriculture have an official stance of “no wood shelves”. But in both states if a cheesemaker gets a thumbs up from the academic expert regarding their maintenance protocol for the shelves, then they have been allowed.
Isn’t that sensible? Did you hear me mention the words “scientific knowledge”? Let’s review what is well researched and known about wood shelves. (I’ll give you some references at the end of this post). Guess how many outbreaks of food borne illness they have been implicated in since the dawn of cheesemaking? Zero. This doesn’t mean that pathogens can’t exist on a wood shelf. If a cheese is contaminated and the wood poorly cared for, it will pass it to the shelf, no matter what material it is made from. Contamination of any aging shelf can happen when poor practices occur at any stage of cheese production, but it is not any more likely when wood is used. Bottom line.
Pros and Cons
So why do cheesemakers and affinuers (the folks that age cheese) love wood shelving? Tradition? Romance? Practicality? In the days before the invention of plastic, that ubiquitous, malleable material that we now take so for granted, wood was the logical and singular option. But fortunately it was also perfect. Like naturally aging cheese, wood “breathes”, it holds moisture without being wet, pulling it both out of the cheese, but also helping keep the aging space at a steady level of humidity. Not unlike the natural stone walls and bricks of the pre-modern aging space. Wood shelves used in aging room also take on the same family of fantastically helpful microflora – yeasts, molds, and especially bacteria – that help create distinctive, out-of-this-world cheeses. The usefulness of these microbes has not only to do with flavor, but also with the final safety of the cheese.
Given what I have just told you about how awesome wood shelving is, why isn’t everyone using it? (At least 60% of American Cheese Society cheesemaker members do) Or at least trying to use it? First it is, not surprisingly, highly discouraged thanks to the stance of our federal friends. Second, the knowledge of how to properly care for wood is tucked away in the minds of a few and only a smattering of books and papers. Third many make only fresh cheeses where aging is not used. And finally, it is more work. More work is not what most cheesemakers need or can even contemplate. Let me tell you about our experience with wood shelves in our own aging room.
Wood Shelves at Pholia Farm
A few years ago we got permission from our inspectors to use wood shelves as long as we consulted with Dr. Lisbeth Goddik,Oregon State University’s Dairy Extension Specialist – a darned amazing woman. She suggested routine cleaning of the shelves with mild soap and warm water, then after rinsing with plain water either wiping the boards down with vinegar or a lactic acid bacteria wash. We did both. We marked which side of each shelf was treated with vinegar and which with bacteria. After aging the cheeses for many months, and before selling them, we swabbed the shelves and sent samples of the cheese to Agrimark lab. All results, for cheese and shelves, whether vinegar or lactic acid bacteria washed, were free from pathogens. So why did we stop? Ironically enough it was another aging room reality that is on the FDA’s hit list (not recent hits list…) cheese mites. I won’t go into too much detail about these little buggers (see one of my most popular posts for all of the itchy details), but what is pertinent is that the dark underside of the cheese sitting on the board was very desirable real estate for the mites. This required more frequent cheese rind labor, something that we were not prepared to do at that time. But I am now.
So Why the Ruling?
Consider for a moment that the FDA is tasked with an enormous responsibility. As that responsibility grows and food systems expand it becomes more expeditious to simplify. This means generalized rules that apply to everyone – versus thoughtful, logical exceptions. Think about it, before a couple of decades ago, you would be hard pressed (like one of those fabulous wood aged European Comtes) to find any US made cheese that was aged in a cellar type situation with a natural rind. Consequently the paradigm for aging became a squeaky clean walk in cooler. The regulations that developed reflected that reality. With the looming burden of the Food Safety Modernization Act, it’s not surprising that they are now seeking to streamline and enforce existing regulations, rather than allow states to take the responsibility of allowing exceptions.
As we move forward as cheesemakers, I think we need to nurture a new paradigm, one in which the aging room is not treated as a processing room, but as a separate type of space in which a different set of GMP’s apply. When I was at a cheese science conference in England, it was repeatedly said that “The dairy/cheese plant is NOT A HOSPITAL”, nothing could be more true in a room in which you are counting on microbes to flourish.
What Can We Do?
I am a member of the American Cheese Society’s Regulatory and Academic committee. This morning (June 10th) we finalized the press release and position of the largest body of cheese professionals in the United States. (See the document at:
So support ACS (join if you are not a member), contact your state representatives, let the FDA know how you feel, and most importantly keep buying and making great cheese! Now, I am going to go put those beautiful Pacific maple shelves back in the aging room. Watch out cheese mites, I’m watching you!
The best overall summary of the topic: Donnelly, Catherine, Cheese and Microbes (2014), American Society for Microbiologists, 171-174
Ak, N. O., Cliver, D. O., & Kasparl, C. W. (1994). Decontamination of Plastic and Wooden Cutting Boards for Kitchen Use. Journal of Food Production, 57, 23–30.
Guillier, L., Stahl, V., Hezard, B., Notz, E., & Briandet, R. (2008). Modelling the competitive growth between Listeria monocytogenes and biofilm microflora of smear cheese wooden shelves. International Journal of Food Microbiology, 128, 51–57.
Mariani, C., Briandet, R., Chamba, J.-F., Notz, E., Carnet-Pantiez, A., Eyoug, R. N., & Oulahal, N. (2007). Biofilm ecology of wooden shelves used in ripening the French raw milk smear cheese Reblochon de Savoie. Journal of Dairy Science, 90, 1653–1661.
Mariani, C., Oulahal, N., Chamba, J.-F., Dubois-Brissonnet, F., Notz, E., & Briandet, R. (2011). Inhibition of Listeria monocytogenes by resident biofilms present on wooden shelves used for cheese ripening. Food Control.
Nese, AK, Cliver, Dean, Kaspar, C. (1994). Cutting Boards of Plastic and Wood Contaminated Experimentally with Bacteria. Journal of Food Protection, 57(1), 16–22.
Oulahal, N., Adt, I., Mariani, C., Carnet-Pantiez, A., Notz, E., & Degraeve, P. (2009). Examination of wooden shelves used in the ripening of a raw milk smear cheese by FTIR spectroscopy. Food Control.
Schvartzman, M. S., Maffre, A., Tenenhaus-Aziza, F., Sanaa, M., Butler, F., & Jordan, K. (2011). Modelling the fate of Listeria monocytogenes during manufacture and ripening of smeared cheese made with pasteurised or raw milk. International Journal of Food Microbiology, 145 Suppl 1, S31–S38.
Zangerl, P., Matlschweiger, C., Dillinger, K., & Eliskases-Lechner, F. (2010). Survival of Listeria monocytogenes after cleaning and sanitation of wooden shelves used for cheese ripening. European Journal of Wood and Wood Products, 68(4), 415–419.
Lasagna Cheese – All in one pot recipe for Mozzarella and Ricotta
While writing an article for Culture magazine on how to make Burrata, I realized how easy it is to make both quick mozzarella and ricotta at the same time, literally within one hour. An email from a reader mentioned that it was her goal to make all of the ingredients for lasagna, so I put this recipe together for anyone out there who has wanted to do the same. This works great for traditional lasagna as well as spaghetti squash, eggplant, or gluten free noodles.I am giving directions using store bought milk, simply to address the availability for most, but any good quality milk will work. We, of course, use our goat milk. Enjoy!
Ingredients and Equipment
1 gallon whole, pasteurized milk
1 ½ teaspoon citric acid dissolved in 1/8 cup cold, non-chlorinated water
1/8 teaspoon double strength rennet mixed into 1/8 cup cold, non-chlorinated water
1 Tablespoon salt
Heavy bottomed stainless steel pot
Large pot for water bath
Large skimmer ladle
Cheesecloth or butter muslin
Large bowl filled with 2 quarts cold water and 1 teaspoon salt
Make the Mozzarella
Place smaller pot inside of larger and pour 3 quarts of the milk into the smaller pot. Set remaining quart aside for ricotta. Add water to larger pot so that it covers the sides of the smaller pot, but doesn’t make it float.
Stir in citric acid solution.
Slowly heat the milk to 95F and turn off heat or remove from burner, leaving in water bath whose temperature is 100-105F
Stir in rennet solution using an up and down motion, not swirling, and let set without movement for 5 minutes. At the end of this time the milk should have coagulated into a heavy custard.
Cut the coagulated milk into 3/8 inch columns and a few horizontal cuts at about the same interval. Let set for 5 minutes.
Heat and agitate or stir the curds, depending upon their firmness (see sidebar), over 5 minutes to 105-108F.
Line colander with cloth and ladle curds into cloth, cover and let drain, flipping curd mass as a whole inside cloth every 5 minutes.
Make the Ricotta
Place the pot containing the whey on direct heat and bring temperature up to 175F, stirring. Remove any bits of curd remaining and add to colander.
When 175F is reached, stir in 1 quart of milk. It should immediately coagulate into ricotta curds. Stir for a minute then use the small sieve to remove the curds from the hot whey. Reserve whey.
Drain ricotta for about 3 minutes then place in bowl.
Stretch the Mozzarella
Stir two tablespoons of salt into whey and verify temperature is still 175F
Cut the mozzarella curd mass into 8 pieces. Drop into the hot whey for several moments. Check a chunk for stretch. When curd is pliable, place the entire mass on aplate and gently work the curd by folding it in toward the center in a circular pattern. Reheat as needed to maintain a pliable texture. Repeat the process about 2 times, just until the curd becomes shiny, then form a ball or loaf.
Place in the cold water bowl just long enough to firm it up, then serve or store for later. Use within a day or so for the best texture.
Mozzarella Tips and Tricks
Traditional, cultured mozzarella making is an all-day process. Quick “30 Minute” recipes have the advantage in near instant gratification – but at a price. Fast recipes for making stretched curd cheese rely upon a lucky combination of added acid, great milk, and deft craftsmanship. While mastering these types of recipes be patient with yourself and with the milk! Here are some tips for success:
Measure the citric acid very carefully. If you use too little or too much the curd will not stretch. Often the amount must be adjusted to suit the milk for the next batch.
Use the freshest milk possible. Do not use ultra pasteurized milk. Most milk available from the grocery store will make quite decent quick mozzarella, but it must be handled very gently. Often it cannot be stirred during step 6, but must instead be agitated by gently swirling or shaking the pot. Farm fresh milk will usually create a much more resilient and malleable curd.
Think of working pasta filata cheese curd as if it is a delicate pastry, rather than bread dough. Too much kneading and working will result in a tough, rubber like texture.
Don’t leave the curd in the hot whey any longer than necessary or you will overheat the fat and lose it from the curd.
If your Quick Mozzarella doesn’t always turn out perfectly, despite many recipe’s suggesting that it is “so easy”, stop blaming yourself! Stretched curd cheeses, often referred to by their Italian name of “pasta filata”, depend upon some pretty precise chemistry occurring in order to turn out well. In this article I have extracted a bit of what I cover in an entire chapter in my book “Mastering Artisan Cheesemaking” on the subject of stretched curd cheeses. I have included three recipes, from Quick to Long.
The Chemistry of Stretching
Before curd can stretch there must be specific changes in the protein structure. For those changes to occur, the curd must reach the magic pH level of about 5.2. Through the development of acid, calcium is removed from the protein structures, allowing for the formation of the right kind of protein network for stretching. (You can read more about how calcium and other minerals interact with acid in chapters 1 and 3 of my book.) To successfully make these cheeses, you need to be able to monitor the development of acid. A pH meter is the easiest method, but I’ll be telling you how to perform a stretch test on your curd that will tell you the same thing (this is the way they did it in “the old days”).
Stretched curd cheeses are heated in hot whey or a water before they are stretched. In addition to getting the curd to the right temperature at which the protein structure can begin to elongate and move, this high-heat treatment essentially (but not by legal definition) pasteurizes these cheeses. Any culture remaining will be killed as well—one more reason it is important to be sure to have the proper acid development before you try to stretch the curd. Some of the coagulant used will be deactivated, too, causing changes in the breakdown of protein during aging. But the enzymes remaining from the starter culture should provide plenty of protein breakdown power if you are making an aged version of this type of cheese.
Let’s go over the two main approaches to making these cheeses – the quick, added acid method and the long, traditional method. You can also combine the two, as Christy Harris has done in the recipe she provided for my book. If you are making a variety that you want to age, go for the traditional approach!
Why Quick Recipes aren’t always Simple
Quick, easy recipes for mozzarella rely upon the addition of a food acid, almost always citric acid, at the right level to lower the milk pH to the magic 5.2 range. If the milk starts out at a different pH than usual, though, and your measurements are not precise (frankly measuring with a teaspoon is never that exact) then you may end up with a pH above or below the needed level. Too low or too high and the curd won’t stretch. Because the acid is added when the milk is still a liquid, you can’t perform the old fashion stretch test that I am going to tell you about in a bit to determine if the acid level is perfect, but you can use pH strips or a pH meter. Still, these recipes works more often than not and you can increase your odds of success by weighing the calcium chloride and then keeping a good record of the results.
While many quick mozzarella recipes call for using a microwave to heat the curd, skip this approach and use the whey. It is just as easy, in my opinion, and less messy, more accurate, and better for the curd. Microwave ovens rarely, if ever, heat the curd evenly. Even heating is quite important to the process.
You can make quick mozzarella with any type of milk- cow, goat, or sheep. Pasteurized is fine, but not ultra-pasteurized (as many of the proteins have been damaged and will not allow the curd to form and/or stretch). Quick mozzarella cannot be aged, since there are no starter bacteria cultures to protect and enhance the cheese during aging. So plan on using it quickly (perhaps that is what the name actually refers to!) If held in the fridge for a few days, even easy recipes will take on lovely melting qualities for pizza cheese. If you want to keep it soft and tender, you can store it in a bit of whey in the fridge. If the cheese becomes too soft or mushy when stored this way, add a bit of salt and calcium chloride to the whey next time. (more on that at the end of this post)
Traditional Pasta Filata Methods
Mozzarella, Provolone, Caciocavallo, and Queso Oaxaca are just a few of the cheeses made using the pasta filata techniques. Very few commercially available versions are still made by hand, but you can find a few stalwart artisans carrying on these traditions today. If you have made traditional cheddar cheese, prepare to be surprised at how similar the process is, except for the stretching. It is believed that the Britons learned the many of the processes of cheddar making by watching the Roman invaders make mozzarella type cheeses.
Traditional pasta filata cheeses develop the right amount of acid after a long ripening period, partially in the whey and partially after the curd is drained and kept warm. When the goal pH nears (or you think it is almost ready) a stretch test should be done. A piece of curd is heated in hot whey or water and tested for its ability to stretch. After heating the chunk, fold it in on itself a few times, observing the texture. If it folds easily, heat it again and fold again. Then heat a third time and try pulling the piece away from itself. If ready, it will stretch into a long, thin strand. At this point the rest of the curd can be stretch or cooled and frozen for future shaping. (In some parts of the country you can buy curd ready to stretch).
Some recipes use Mesophilic cultures, others Thermophilic and still others a combination of bacteria. Old world recipes often use raw milk and rennet paste (producing a sharp, piquant flavor). Lipase can be added to help emulate this more complex flavor profile.
When using the whey from making traditional and hybrid mozzarella, it is a good idea to first heat the whey until the proteins left in the whey precipitate out of the liquid, usually at about 185F. Skim these delicious real ricotta curds off of the top with a sieve and drain. Then let the whey cool to 175-180 for stretching the curd.
When the curd is ready to stretch, it is a good idea to cut it into small chunks before heating, as this will help heat it evenly. I suggest using a small strainer basket or sieve to lower the curd into the hot whey. When beginning to work the curd, use gentle folding motions, bending the sides in towards the back of the mass (if you have ever made a loaf of bread, the motions are almost identical). At any time when the curd becomes too cool to move easily, reheat it! When the mass is shiny, usually after a couple of rounds of folding and heating, then it is ready to shape. If you are making “string” cheese or a skein (as with queso Oaxaca or queso asedero) then put the curd through several stretching sessions to continually elongate and align the protein networks. When the final shape has been attained, cool the cheese in water. Salt can be added to the heating water and/or the cooling water.
Stretched Curd Cheese Recipes
Quick and Simple Mozzarella
1 gallon milk
1 ½ tsp citric acid dissolved in ¼ cup cool water
¼ tsp calcium chloride dissolved in ¼ cup cool water
1/8 tsp double strength rennet dissolved in ¼ cup cool, non-chlorinated water
Combine milk, citric acid solution, and calcium chloride solution.
Warm milk to 90 F, stirring evenly.
Remove from heat and stir in rennet solution with an up and down motion. Still the milk, cover and let set for 5 minutes until curd is well gelled.
Cut the curd into ½ inch pieces let set for 2 minutes.
Stir and heat the curd to 105 F over 5-10 minutes or until curd starts to feel somewhat “plastic” or gooey.
Place a colander over a pot and pour curds into it, reserving the whey. Cover curds.
Heat whey to 175-180F.
Cut up curd mass into 1 inch chunks then lower them in 1-2 cup amounts into hot whey.
Stretch, following stretching tips earlier.
Hybrid Method Mozzarella
1 gallon milk
1/16 tsp TA 60, 1/16 tsp MM OR 1/8 tsp MA 4000
¼ tsp calcium chloride diluted in 1/8 cup water (optional)
¼ – ½ tsp citric acid dissolved in 1/8 cup water
1/8 tsp double strength rennet diluted in 1/8 cup water
1. Warm ½ gallon of the milk to 96F
2. Add cultures, let set for 5 minutes then stir well for 3-5 minutes
3. Add calcium chloride solution (optional)
4. Maintain at 96 F and ripen for one hour, goal pH is about 6.2
5. Combine citric acid mixture with the other ½ gallon of milk and warm to 96F, goal pH about 6.0
6. Combine two milk mixtures, goal pH about 6.1
7. Verify temperature is 96F and add rennet solution stirring with an up and down motion for about 15-30 seconds
8. Still the milk and let set for 30 minutes or until ready to cut
9. Cut into 3/8 inch chunks, rest 5 minutes
10. Gently stir and heat to 115F over 30 minutes.
11. Turn off heat and let settle for 5 minutes
12. Pour off the whey (saving) and pour curds into cloth lined colander. Set over the drained whey, cover, and keep curds at 102F, turning mass every 30 minutes, until curd passes the stretch test (described earlier).
13. Heat whey to 180F and follow stretching directions
Traditional Style for Aging
2 gallons milk
1/8 plus teaspoon Thermo B
½ tsp calcium chloride diluted in 1/8 cup cool water (optional)
1/16 teaspoon double strength rennet diluted in 1/8 cup cool water
Warm milk to 80F and sprinkle cultures on top. Let set 5 minutes. Stir well.
Increase temperature to 90F and hold for one hour.
Stir in calcium chloride if using.
Stir in rennet solution with an up and down motion for one minute. Still milk and let set quietly until clean break is achieved. Goal coagulation time is 45 minutes.
Cut curd into 3/8 – ½ inch chunks, rest 5 minutes
Stir gently and heat slowly to 95-98F over 15 minutes. Then stir and heat to 118F over 30 more minutes. Hold at 118F, stirring occasionally to keep from matting, until curd pH is 6.0. This may take 60-90 minutes.
Drain the curds (saving whey) in a colander. Cover colander and place over warm pot, keeping the curd temperature at about 102-104 F.
Turn curd mass every 30-45 minutes until curd pH is about 5.2 or when curd passes stretch test.
Heat whey to 180F, add a pinch of salt and follow stretching directions. Curd can also be chilled and saved to stretch later (it can also be frozen).
Quick versions of mozzarella can be stored in the refrigerator for a few days, but will not age safely. They are best used fresh! The traditional method can be used fresh, stored in a light brine made from whey, smoked, and aged. The hybrid method can also be aged, but will likely be a little less complex do to less bacterial activity.
Storing in whey/brine:
Mix one quart of filtered (through cloth) whey left over after stretching with an 1/8 teaspoon of salt. This amount can be adjusted depending upon if you salted the whey during stretching or the water during chilling. The saltier they mixture, the more firm the cheese will be, so if you want it tender, you may want to omit the salt completely.
Immerse small balls or discs of fresh mozzarella in the solution. A ziplock type bag can be used – squeeze the extra air out of the bag so that moisture surrounds the balls. This method requires less liquid.
If the liquid becomes cloudy or the cheese starts getting soggy or soft, you probably need to add a bit of calcium chloride to the brine. Try about ¼ teaspoon per quart. Adjust up if the cheese continues to soften and less if the cheese becomes too firm.
Probiotics. The new darling of health and advertising. Do cheeses really contain any of these amazing, essential microbes?
While I have no letters after my name (unless I capriciously add them), it doesn’t require a university degree to understand that bacteria, both beneficial and hurtful, can only live under certain contidions. I am a cheesemaker and I study science as it relates to dairy. I know what cultures I add to milk to make cheese. Very few of these are currently considered probiotic. And even if they were, when cheese is aged, the bacteria gradually die off as they run out of food to metabolize. So even when probiotic cultures are used, they do not survive longterm aging*. In fact, I was at a conference in England this last summer where research into genetically modifying probiotic bacteria to survive cheesemaking and aging was discussed. (Without much enthusiasm on the part of the artisan cheesemakers present, I might add!)
* I did find that some aged cheeses are commercially being designed to include probiotic bacteria that survive long term aging. These cheeses are labeled as containing probiotics and are not available widely as of yet. I think you can expect to see more products such as this in the future- if nothing else, they will be introduced for the market value they will bring.
I was doing some research today for my latest book (on raw milk production and consumption). I was reading a on probiotics that I chose for it’s high ranking and great reviews on Amazon. After perusing the front chapters, I skipped to the section containing information about cheese and dairy products – and immediately had to begin putting yellow highlighter frowny faces in the margins (my system for reviewing books). At first I wondered if perhaps my information was wrong, but then found another contradiction that basically confirmed that the author was not really aware of at least this portion of his subject. (I sure hate it when what you think is going to be a reputable source, turns out to be suspect.)
So lets go over a few basic things that you can always apply to probiotics -to help determine for yourself if a food is a good source of these helpful bacteria.
In order to be probiotic, the bacteria must survive the harsh environment of our stomach and travel on to the next portions of our digestive system. Not very many bacteria have this capability – the stomach is one of the first defenses against bacterial contamination of food!
Probiotic bacteria in food must have a source of nourishment – or they will die (unless, of course, they are held in stasis through something such as freezing). This is true of all bacteria. Once a food is fully fermented, the bacteria begin to perish unless fermentation is suspended – through refrigeration or some other means. Even then, their life span is limited.
High heat, such as scalding or boiling, kills all but bacteria that are capable of forming spores that protect them from the heat. So even if milk or cheese or whey contains probiotic bacteria if it is cooked they will die.
The bacteria currently considered probiotic include only a couple of strains regularly used in making cheese. A fresh cheese that uses these bacteria as a part of its fermentation process will likely have some of these helpful microbes still living, but the longer a cheese is aged, the fewer bacteria remain alive. Aged hard cheeses are not sterile, but the life forms found on and around them are typically environmental, not those that were added during the cheesemaking process. In cheeses made using high heat and added acid, such as whey and milk ricotta, any probiotic bacteria in the whey will be killed during the high heat treatment (along with enzymes and milk’s natural defensive systems).
Bottom line, don’t look to aged cheeses as a probiotic source, yogurt is a no-brainer if probiotics are your goal! Instead, enjoy aged, natural cheeses for what they are meant to be – deliciously preserved (usually through fermentation) milk.
P.S.: So where can you find information on probiotics that you can trust? Hard to say! Popular topics are a magnet for publishers and writers. The best advice is to consult more than one source, preferably those that list scientific studies as their sources – but of course all the studies that will be helpful have not been done, nor is science a static subject.
Oh, here are a couple of sources I used to write this post:
Vet. Med. – Czech, 47, 2002 (6): 169–180 Review Article 169 – Lactic Acid Bacteria, Probiotics and the Immune System
R. HERICH, M. LEVKUT
Department of Pathology, University of Veterinary Medicine, Košice, Slovak Republic
J Dairy Sci. 1987 Jan;70(1):1-12.
Survival of lactic acid bacteria in the human stomach and adhesion to intestinal cells.
Conway PL, Gorbach SL, Goldin BR.
I was recently visiting England to attend “The Science of Artisan Cheesemaking” conference and had the great additional luck to visit an amazing farmstead creamery- Hill Dairy in Somerset. Not only was the facility quite possibly one of the most well thought out and constructed small creameries that I have ever visited, but owners Will and Caroline Atkinson, were as charming and lovely as their picturesque English farm. Since I got back to the US, we have been corresponding about a problem that Hill Dairy was experiencing both during my visit and on and off for a good part of this fall. A problem, unfortunately, that caused the loss of many batches of cheese milk and is a problem that plagues many farmstead cheesemakers (sometimes even without their knowing). High coliform counts.
First a bit about the large bacterial family called coliforms. These microbes live in the environment of the farm, especially bedding, feed, and soil. But some of them also live in the lower intestine (not only of cows and goats, but of people too) the most well-known being Escherichia coli, better known by its abbreviated name “E. coli”. The presence of E. coli in milk or cheese can be translated as the presence of feces, that’s right, poo. While E. coli and poo in milk are not desirable in any circles, it doesn’t necessarily mean that the milk is unsafe. It is the ne’re-do-well coliform cousin E. coli 0157:H7 that can wreak horrible damage when ingested. (There is another variant that surfaced recently in Germany that is just as nasty and there will no doubt be more variations in the future that will cause horrific food borne illnesses, sickness, and death). So while coliforms do not necessarily mean the presence of pathogens (illness causing microbes) their numbers are a good gauge of milk cleanliness. The higher the general coliform count, the higher your odds that some might be bad.
Currently most data say that high quality raw milk should have fewer than 10 cfu’s (that’s colony forming units) per milliliter of milk. Some states allow for higher counts and the “fewer than 10”number is somewhat arbitrary, but let’s pretend for now that it’s a great standard. Here at our farm our petri-film plate counts (done on every cheese batch – see my previous posts if you want to know how to do these) show our total coliforms at usually 3-5 cfu’s per ml. Awesome, right? Well, when I got back from England our counts shot up to over 400cfu/ml. Fortunately for both us and Hill Dairy, tests showed that none of the coliforms were from fecal sources, no E. coliforms. (You can buy petri film plates that will grow E. coli’s in a different color than regular coliforms). Interestingly, but not surprisingly, our APC (which counts total bacteria numbers) didn’t look that bad – until you looked closely and could see that there were tiny air bubbles all over the plate (from the gas produced by the coliforms) and these bubbles had lifted the film from the plate – making it look as though there were not that many colonies growing.
So what do high numbers of “harmless” coliforms do to milk and cheese? Well, these guys eat lactose – that’s milk sugar, (as do starter cultures) and produce both lactic acid and carbon dioxide – that’s gas. The problem with them is that they grow very fast and can often out-compete the added starter culture during a slow fermentation, just like what is done to make most fresh cheeses and lactic set bloomy rinds (like the Atkinson’s were making – and yes it is legal to make them with raw milk in the UK). At Pholia Farm, we make long-aged, low moisture cheese that use a faster acid development and rennet, so we would not have known about our high coliform counts if we were not doing routine lab tests on every batch. While these coliform types are unlikely to make our cheese unsafe, it tells us that something is far from ideal with our process – something that could lead to unsafe food. We don’t only make cheese, we drink our raw milk – we care that it is of the best quality possible for many reasons.
Okay, so both our farm and Hill Dairy had much higher than normal counts, what did it mean and what did we do about it to resolve the problem? The most common causes of high coliforms are dirty teats, poor milking technique, and dirty equipment. While this may seem like an easy fix, when your counts suddenly go from great to horrendous, it can be very confusing. So let’s go over a step by step procedure for trouble shooting coliform counts – with as little financial investment as possible!
Observe that animals are coming into the parlor relatively free of manure and debris – dairy clipping udders can help.
Verify that established teat and udder cleaning methods are being performed properly and that udder cleaning solutions and sanitizers are effective.
Verify that milking equipment with parts that need replacing, especially rubber parts, are up to date for recommended replacement times.
Verify that cleaning steps for equipment are effective – this includes chemical strength and effectiveness for your water type, temperatures, time, air slug velocity, etc. Swabs can be taken at various points in system and cultured for total bacteria counts to verify effectiveness.
Perform “hyper-cleaning” following guidelines from chemical manufacturer or other dairy representative. This often includes a double strength, double time cleaning and manual cleaning to verify the removal of bio-films and residue that might have occurred from less than ideal parlor practices.
Verify milk chilling process, if used (even with proper chilling, high enough coliform counts will be a problem in lactic technology cheeses)
Don’t be surprised if trouble shooting takes place over many days before you completely conquer the problem. All it takes is one step to be missed, and the problem reasserts itself. For example, our problem seems to have come from our neglect (later in the season) of dairy clipping our ladies udders, combined with wet weather, combined with me forgetting to replace a couple of rubber parts inside of the milking claws , combined with a bit too casual milking and udder cleaning techniques. I would fix one problem, but not all problems at one time. Everything needed to be zeroed out, you might say, before our counts went completely back to our normal low. It took several weeks of implementing new techniques and replacing parts and hyper-cleaning to shape things back up. During that time the count dropped from the 400, to 100 plus, then to the high 30’s, and finally to under 10.
If you experience a similar extended issue, here are some things you can do so that you don’t lose product, and future income, while you whip things back into shape:
Pasteurize the milk.
Thermize, aka heat shock, the milk (lower temperature than pasteurization, not recognized in the US, so cheeses made from thermized milk are not considered pasteurized)
Switch from lactic cheeses (such as surface ripened and fresh soft) to an aged, quickly cultured and rennet style cheese. (Verify that no E. coli is present)
Switch from freeze-dried direct set culture to bulk starter or mother culture that will provide a faster growing starter bacteria population. (if coliform counts are too high, though, this may not be enough)
Remember that if you are not testing each batch of cheese milk and are making a rennet coagulated, quickly acidified cheese, you may never know that your milk is less clean than it could be! If you do experience a problem, don’t feel alone and remember that keeping sanitation standards high on the small farm, or any farm for that matter, is an ongoing, major challenge. It is a great reminder of how quickly things can change – for the worst.