Temperature is Everything in Cheesemaking!
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Most cheesemaking recipes only call for three or four ingredients, yet hundreds of different kinds of cheese exist. We can make so many varieties from such a short list of ingredients because when we vary the amounts of the ingredients, along with the time, temperature, and techniques we use, the cheeses will take on entirely new characteristics; of all these factors, temperature is probably the most impactful.
How does temperature affect your cheesemaking efforts? There are many points in the process where it is vitally important, starting with the milk itself.
People who have their own supply of milk may decide to drink it and make cheese with it fresh from the udder while it’s raw. In most cases, this can be safe and nutritious as long as the animals are healthy, the milking process is very clean, and the storage/cooling of the milk is prompt and adequate. The raw milk must also be used quickly — preferably within 24–48 hours after milking to be the safest. Regardless of your views on raw milk, many people prefer to pasteurize their milk (for safety, consistency, and longevity), or they may only be able to buy pasteurized milk in their local market. Each option has pros and cons, and we’ll save that discussion for another day. But suffice it to say pasteurized milk may be easier to come by, and you can make cheese with much of it, but not all pasteurization temperatures are created equally.
Here are the four main categories of pasteurization most widely available.
- Vat Pasteurization 145 degrees Fahrenheit (63 degrees Celsius) for 30 minutes
- HTST (high temp short time) 161 degrees F (72 degrees C) for 15 seconds
- UP (ultra pasteurization) 280 degrees F (138 degrees C) for 2 seconds
- UHT (ultra-high temperature) no set time and temperature — based on commercial equipment involved and requires aseptic conditions and hermetically sealing the containers)
The first two lower temperatures will work fine for cheesemaking. Some people believe that vat pasteurization causes less damage to the milk than HTST. I’ve talked to several dairy inspectors who feel that the shorter time involved in the HTST process actually results in less damage to the milk. My own experience with both methods is that there is little or no difference in the taste and texture of my final cheeses, but the HTST method sure is a lot quicker, so it’s my preferred choice.
The UP and UHT milks, however, are so compromised and damaged from those high temperatures that they simply will not make cheese. If you think about it, the whole goal of those methods is to extend shelf life. In other words, to keep your milk from curdling or becoming cheese. This is fine if you want to keep a container of milk in the refrigerator (or in the pantry in the case of UHT) for a long time, but it’s the kiss of death if you actually WANT your milk to become cheese!
The next point in your cheesemaking where temperature is important is when you add the culture and allow the bacteria to “ripen” the milk. Most recipes have you add culture around 85–90 degrees F and let it sit for anywhere from 15 minutes to an hour or so. Some recipes ripen at lower temperatures (70–75 degrees F) for 12 to 20 hours. During the ripening time, the bacteria in the culture consume the lactose (milk sugar) and convert it to lactic acid. As more acid is produced, the pH level in the milk goes down. More acid makes for a stronger, sharper flavor to the final cheese. Lower temperatures at this stage will slow acid production, while higher temperatures will speed it up.
After the milk is ripened, most recipes call for the addition of rennet to coagulate the milk. This enzyme works most effectively and efficiently around 90 degrees F and takes anywhere from 15 minutes to a little over an hour to do its job. These recipes — for cheeses like feta, camembert, and most hard cheeses — are often referred to as “fully renneted” cheeses. That means they use a lot of rennet (1/4 to ½ tsp per gallon) for a short amount of time. Those lower-temperature cheeses, like chevre and cream cheese, are referred to as “rennet-assisted” because they use less rennet (usually just a drop or two) along with a longer coagulation time (12 to 24 hours). As with the ripening process, the coagulation process will go faster at higher temperatures and take longer at lower temps.
Temperature During the Cooking Process
After coagulation has been achieved, many recipes (especially those for harder, pressed cheeses) have a period of heating and stirring the curd once it has been cut. While we often refer to this period as cooking, the heat usually stays pretty low* (100–120 degrees F) to keep the culture from being killed. While heating and stirring, it’s important to increase the temperature very slowly and not to go too high. This is because as we heat and stir the curd, it expels the liquid part of the milk (the whey), so it gets smaller and drier. If we go too fast, we can sear the outer edges of the curd and trap whey inside. If we heat too high, we can dry out the curd so much that it becomes harder and crumblier before it ever gets a chance to be pressed. This may result in curds that just won’t knit together to become a wheel of cheese.
* There are some cheeses like ricotta and paneer that do use high temperatures during the cooking stage. These are direct-acidification cheeses, meaning that we add acids like vinegar, lemon juice, or citric acid to both acidify and coagulate the milk. In order for coagulation to happen without any more acidification than would taste good, high heat is needed. And since there is no culture (bacteria) involved with making these cheeses, the high temperatures aren’t killing anything.
Temperature During Pressing
Most cheese recipes that require pressing are pressed at room temperature. While the ideal temperature may be around 72 degrees F, your room temperature on any given day might range from 65 to 85 degrees F (or even lower/higher). Although the initial acid development happens during the ripening stage, it does continue even through the pressing stage. Once you salt the curds, the acid development stops or slows dramatically, but most cheeses aren’t salted until after pressing, so acid development is likely continuing throughout the pressing stage. Like everything else, the lower the temperature during pressing, the slower the acid development, which results in a milder flavor. The higher the temperature, the more acid is created, making the cheese sharper.
Temperature During Aging
Most aged cheeses like to mature at around 50–55 degrees F. This process can take anywhere from one month to a year or more, depending on the type of cheese being made and the results desired. The bacteria in the cheese, the enzymes, yeasts, and various molds continue to change and evolve throughout the process. The longer cheese ages, generally the more flavorful and drier it gets. Different varieties peak at different points in time, but like everything else, things happen faster when it’s warmer and slower when it’s cooler.
Most of the ingredients aren’t too different between cheeses, other than perhaps the addition of a secondary culture like penicillium candidum for bloomy rinds or another enzyme like lipase for a more piquant flavor. It’s the variation in temperature at each stage that really can make a big difference. By paying close attention to the temperature requirements at each stage of your cheesemaking process — from milk selection to the aging of your cheese — you will ensure that the cheese you set out to make actually becomes that particular cheese!
Originally published in the May/June 2023 issue of Goat Journal and regularly vetted for accuracy.