Raw milk yogurt is delicious and full of beneficial bacteria from both the raw milk and the yogurt culture. When using raw milk to make yogurt, there are several factors that must be considered including how the bacteria content of the raw milk affects the yogurt culture, the consistency of raw milk yogurt, potential risks within the process, and more. Following the discussion of these special considerations are detailed instructions for each of the three methods available for making raw milk yogurt.
Special Considerations when Making Raw Milk Yogurt
Making yogurt with raw milk differs from using pasteurized milk and several factors should be considered.
Bacteria Content. We recommend using only fresh milk to make yogurt. Raw milk comes with its own set of beneficial bacteria, and if your milk is a few days old or wasn't chilled down quickly enough before you bought it, that bacterial count can be high. This means that the culture you introduce to make your yogurt could have some hefty competition, which can lead to yogurt with an “off” flavor, or yogurt that does not set properly.
Raw Milk Fat Content. While you can make yogurt with raw milk of any level of fat content, there are a few factors to consider. First, milk with higher fat content will generally yield thicker yogurt (see below). Second, because raw milk is not homogenized, be aware that as the milk cultures and the yogurt sets, the cream will rise to the top. So the top layer of your raw milk yogurt will be more yellow and of a much thicker consistency. The cream layer can be scooped off and eaten alone or mixed into the yogurt.
Consistency. Raw milk generally makes yogurt that has a much thinner consistency than yogurt made with pasteurized milk. Pasteurization damages proteins and a byproduct of that damage is thicker yogurt when the milk is cultured. While raw milk with a high fat content will yield thicker yogurt than lower-fat raw milk, overall raw milk yogurt will have a thinner consistency when compared to yogurt made with pasteurized milk. There are several ways to thicken raw milk yogurt. The most desirable is to strain the yogurt using tight-weave cheese cloth or a tea towel, thereby removing some of the whey and leaving a thicker consistency yogurt. (This method also produces raw cultured whey which can be used to culture vegetables, soak grains and flour, as a base ingredient for a smoothie, etc.) An alternative option is to add dry milk powder, agar flakes, or tapioca powder to the yogurt as a thickening agent.
Risk. Although most people who consume raw milk do not feel that raw milk is inherently dangerous, there are risks to everything and people have become ill from raw milk. (It is also possible to become ill from pasteurized milk.) Talk to your farmer, do your research, and decide whether or not these risks are worth it.
Perpetuation of the Culture. Some varieties of yogurt starter are meant to be used once while others are meant to be perpetuated from batch-to-batch. Caution must be taken when using a perpetuating yogurt starter with raw milk as the beneficial bacteria present in raw milk make the perpetuation process more difficult and uncertain. Over time, the bacteria in the raw milk will generally weaken the yogurt culture so if you try to perpetuate one batch of raw milk yogurt to another, eventually the milk bacteria will present too great a challenge and the yogurt starter will stop culturing the milk effectively. If using a perpetuating yogurt culture, it is safest to first make a mother culture so you can use the mother culture to inoculate each batch of raw milk yogurt and keep your yogurt starter healthy. (See below for detailed instructions.) No special perpetuation steps are necessary if using a direct-set (one-time-use) variety of yogurt culture.
Methods for Making Raw Milk Yogurt
There are three general options for cultures for making raw milk yogurt. Yogurt starter cultures can be divided into two groups: thermophilic (heat loving) and mesophilic (low temperature), which refers to the ideal temperature range for culturing each type of yogurt. Yogurt cultures also come in two varieties that determine how the culture is used: direct-set (one-time use) or a perpetuating variety where a small amount of a previous batch is used to make the next batch. There are advantages and disadvantages to each type when working with raw milk.
Option #1: Direct-set Thermophilic Yogurt Starter
A direct-set thermophilic yogurt culture is one of the most popular methods for making raw milk yogurt. Direct-set yogurt cultures are one-time-use cultures. Either one of the following can be used as your starter culture:
A packet of freeze-dried powder that is stored in the freezer and used to inoculate each batch OR
A small amount of yogurt from the store. If using ready-made yogurt as your starter, be sure to use an unflavored variety that is labeled as containing live active cultures.
Thermophilic direct-set starter cultures are known for making thicker consistency yogurt compared to perpetuating varieties of yogurt starters. Direct-set cultures work well with yogurt makers or a similar heating appliance or heating method as the milk must culture at around 110°F to properly set the yogurt.
Instructions. Heat the raw milk to 110°F. (Food heated to 110°F is generally still considered raw.) If using a freeze-dried yogurt culture, add the specified amount of culture to the specified amount of milk. If using yogurt from the store as your starter culture, add a tablespoon of yogurt for each cup of raw milk you wish to culture. Stir gently until fully dissolved and well-distributed throughout the milk. Incubate the mixture at 105° to 110°F for 6 to 7 hours until set. Refrigerate prior to eating.
Advantages. Easy to use, packets store in the freezer until you are ready to make yogurt; the culture does not require regular care or maintenance (easy to take breaks from making yogurt using this type of culture); generally makes thicker consistency yogurt when compared to perpetuating cultures.
Disadvantages. Direct-set cultures are one-time-use (generally not able to be perpetuated or with very limited perpetuation lifespan); if using a freeze-dried starter culture each package generally contains 6 to 8 doses depending on the variety; if using yogurt from the store as a starter culture, you will need to buy a new container of yogurt on a regular basis to use as a starter culture.
Option #2 and Option #3 (below) utilize perpetuating yogurt starters. As discussed above, perpetuating a raw milk yogurt from one batch to the next is an uncertain process due to the competition provided by the beneficial bacteria in the raw milk. Over time the raw milk bacteria will weaken the yogurt bacteria and eventually it will not culture the milk effectively. To preserve the health of the yogurt culture, we recommend using the mother culture method for perpetuating the starter culture.
Making a Mother Culture for Yogurt Starter Perpetuation. To make a mother culture, a small amount of milk (generally a cup or less) is heated to pasteurize the milk and provide a blank slate of sorts in terms of bacteria content. The yogurt culture is then added to this cup of pasteurized milk and cultured to create a clean mother culture for use in making raw milk yogurt. A small amount of the mother culture is used inoculate each batch of raw milk yogurt (generally 1-1/2 to 3 teaspoons of mother culture per cup of raw milk depending on the type of culture). A new mother culture must be made at least every 7 days to preserve the health of the yogurt bacteria and ensure it remains active and strong for culturing each batch of yogurt. (A new mother culture can be made using a small amount of the existing mother culture.) Exact instructions for making a mother culture vary slightly depending on the variety of yogurt culture (thermophilic vs. mesophilic) so please consult the specific instructions provided with each packet of yogurt starter.
A perpetuating thermophilic yogurt culture is similar to the direct-set starters in how the yogurt is cultured, but has the advantage of allowing for perpetuation of the yogurt culture rather than buying a new packet of yogurt starter on a regular basis. These cultures work well with yogurt makers or a similar heating appliance or heating method as the milk must culture at about 110°F to properly set the yogurt. As stated above, we strongly recommend using a mother culture to inoculate each batch of raw milk yogurt to preserve the integrity of the yogurt starter.
Instructions. To make a batch of raw milk yogurt, heat one cup of raw milk to 112°F. Mix in 1-1/2 to 2 teaspoons of the pure mother culture. Mix the starter and milk well. You can make larger batches of yogurt by adhering to the same ratio of 1.5 to 2 teaspoons of yogurt to 1 cup of milk. Cover the yogurt and incubate at 110°F degrees for 5 to 7 hours. Once the yogurt is set (when the jar is tipped, the yogurt shouldn’t run up the side of the jar and should move away from the side of the jar as a single mass), allow the yogurt to cool for 2 hours. Place the yogurt in the refrigerator for 6 hours to halt the culturing process. Each batch of raw milk yogurt must use the pure mother culture as the starter culture. Do not try to culture a new batch of yogurt using a previous batch of raw milk yogurt. This will result in a compromised culture and over time your yogurt will no longer culture properly.
Advantages. If the mother culture procedure is used, the yogurt culture can be perpetuated via the mother culture from batch-to-batch; no need to continually purchase yogurt starter.
Disadvantages. Need to create and maintain a mother culture to preserve the health of the yogurt culture when used with raw milk; generally makes yogurt with a thinner consistency than the direct-set thermophilic cultures.
A perpetuating mesophilic yogurt starter is another popular culture for making raw yogurt due to two distinct advantages. First, mesophilic yogurt starters culture at room temperature (70° to 77°F) so they do not require a yogurt maker or any heating device. This is often seen as particularly useful when working with raw milk. Second, the culture perpetuates so there is no need to buy new packets of yogurt starter on a regular basis. As stated above, we strongly recommend using a mother culture to inoculate each batch of raw milk yogurt to preserve the integrity of the culture. One potential drawback to this type of culture is that mesophilic cultures tend to make yogurt with a much thinner consistency than thermophilic cultures. If a thicker consistency mesophilic yogurt is desired, we recommend straining the finished yogurt of some of the whey prior to eating.
Instructions. To make a batch of raw milk yogurt, add 1 tablespoon of the pure mother culture to each cup of raw milk. You can make larger batches of yogurt by adhering to the same ratio of 1 tablespoon of yogurt to 1 cup of milk. Cover the jar with a towel or coffee filter and secure the cover with a rubber band. You can culture with or without a lid. Let the mixture culture undisturbed at 70° to 77°F degrees for 12 to 18 hours. Once the yogurt is set (when the jar is tipped, the yogurt shouldn’t run up the side of the jar and should move away from the side of the jar as a single mass), cover the jar with a lid and place the yogurt in the refrigerator for 6 hours to halt the culturing process. Each batch of raw milk yogurt must use the pure mother culture as the starter culture. Do not try to culture a new batch of yogurt using a previous batch of raw milk yogurt. This will result in a compromised culture and over time your yogurt will no longer culture properly.
Advantages: Cultures at room temperature (70° to 77°F) leaving the raw milk bacteria fully intact; if the mother culture procedure is used, the yogurt culture can be perpetuated from batch-to-batch via the mother culture; no need to continually purchase yogurt starter.
Disadvantages: Need to create and maintain a mother culture to preserve the health of the yogurt culture when used with raw milk; this type of yogurt culture makes the thinnest consistency yogurt.
Available Varieties. We currently carry several varieties of perpetuating mesophilic yogurt starters: viili, filmjolk, matsoni and piima.