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Yogurt Starter FAQ

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Q. What types of yogurt starter cultures do you carry?

A. We carry direct-set and heirloom yogurt starter cultures. The heirloom starters are available in two types, mesophilic and thermophilic.


Q. What is the difference between the direct-set and the heirloom starter cultures?

A. Direct-set yogurt starter cultures are single-use cultures: one packet makes one batch of yogurt. Heirloom yogurt starter cultures are reusable indefinitely, with care. Heirloom yogurts must be recultured at least every 7 days.


Q. What is the difference between mesophilic and thermophilic yogurt starter cultures? 

A. Mesophilic cultures at room temperature, 70º-77ºF. Thermophilic cultures at approximately 110ºF. 


Q. What yogurt starter cultures do you carry?

A. We carry the following starters:


Q. What is the difference between the different starter cultures? What is the flavor, texture, consistency? What types of bacteria are in each?

A. A comparison chart, listing each yogurt culture in detail, may be found here.


Q. How long will the yogurt starter culture last if unopened? What do I do with extra packets of yogurt starter culture?

A. Extra packets of yogurt starter culture may be stored in the refrigerator or freezer. Information on how long each type of culture lasts may be found here.


Q. What ingredients are in your yogurt starter cultures?

A. Ingredients for every culture we carry are found on each product page.


Q. What kind of milk can I use?

A. Any type of pasteurized dairy milk can be used with direct-set and heirloom starters. Raw milk can be used, but when working with heirloom cultures, have special requirements. Alternative milks can be used, but will require thickeners in order to achieve a spoonable consistency.


Q. Why must heirloom cultures be recultured at least every 7 days?

A. In order to maintain culturing viability, to be able to use the culture indefinitely, you must make a new batch at least every 7 days.


Q. Why can’t I reculture a direct-set starter?

A. Direct-set yogurt starters are one-time-use cultures. It is possible to use some yogurt made with a direct-set starter to make a new batch of yogurt, but after a few batches, the culture will weaken and a new dose of direct-set starter is needed.


Q. Why can’t I reculture yogurt made with non-dairy milk?

A. Non-dairy milk is generally cultured using a direct-set starter. Please see previous question. Heirloom cultures consume lactose as their food source and cannot survive long term culturing alternative milk. A dairy mother culture must be maintained and used to culture the non-dairy milk. If you must be completely dairy free, the Vegan Yogurt Starter is your best choice.


Q. Will my yogurt culture better or have more probiotics if I use more than one packet? Can I use more starter culture to achieve a thicker yogurt?

A. Do not use more starter than recommended. Using too much starter can crowd the bacteria, causing the bacteria to run out of food before the yogurt completely ferments the milk. The result is often a thinner, sometimes bitter, yogurt.


Q. Can I combine different yogurt starter cultures or add a probiotic capsule to make a different kind of yogurt or increase the probiotic content?

A. Yogurt cultures are a carefully balanced combination of bacteria that will produce a particular type of yogurt. Mixing different cultures or bacteria together may cause the culture to weaken or die.


Q. Can I use raw milk to activate an heirloom yogurt starter culture?

A. Our yogurt starters are in a freeze-dried state. To safely activate them, we recommend using pasteurized milk (not ultra-pasteurized). To use raw milk, please follow instructions for Making Raw Milk Yogurt.


Q. Can I use goat milk to activate an heirloom yogurt starter culture?

A. Yes, as long as it is pasteurized. If using raw goat milk, follow instructions for Making Raw Milk Yogurt.


Q. Can I use non-dairy milk to activate an heirloom yogurt starter culture?

A. Non-dairy milk will not work to activate an heirloom starter. It must be activated using pasteurized dairy milk.


Q. Can I use raw milk, goat milk, or non-dairy milk with your direct-set yogurt starters?

A. Yes, raw, goat and non-dairy milk may be used with the direct-set cultures. If using raw milk, please follow instructions for Making Raw Milk Yogurt.


Q. Why can’t I use ultra-pasteurized/UHT milk for culturing yogurt?

A. Milk that is “too clean,” such as ultra-pasteurized/UHT milk, or milk that has been heated by microwave, may be too sterile for the yogurt culture to use as nourishment.


Q. Once I’ve activated the yogurt starter culture and used it to make a batch of yogurt, what should I do with what’s left?

A. What you have remaining is yogurt. Eat it plain, sweeten or flavor it and enjoy!



Q. Why do I have to heat pasteurized milk when using thermophilic cultures?

A. Heating the milk to 160ºF will kill any bacteria present in the milk that might compete with bacteria in the thermophilic cultures.


Q. Why do you recommend culturing no more than ½ gallon of yogurt per batch?

A. With that much liquid, it is difficult to keep temperature consistent. If culturing a thermophilic at 110ºF, the outer portion is likely to be warmer or the center will never be warm enough. For mesophilic cultures, it takes a long time for milk come to room temperature and for the culture to begin working while the milk bacteria is building fast and can compete with the yogurt culture.


Q. How do I put my heirloom yogurt starter on hold while I am on vacation?

A. If you will be gone longer than a week, the best solution is to find a friend who can care for your yogurt culture. Another option is to freeze yogurt in ice cube trays to thaw later and use as starter yogurt. Freezing is not a perfect solution but it will usually work as long as the yogurt is only frozen for a short period of time (no more than a few weeks). Learn more here.


Q. Can I switch back and forth between raw milk and pasteurized milk for making yogurt? Can I switch back and forth between cow milk and goat milk? How about between low-fat milk and whole milk?

A. Yes, you can switch between milks for each batch of yogurt. Remember, if you are using raw milk with an heirloom (reusable) culture, you will need to maintain a pasteurized mother culture made in order to preserve the viability of the culture.


Q. How do I know that my yogurt maker is operating at the correct temperature?

A. It is always a good idea to test the temperature of a new yogurt maker or one that has not been used for a long time. Follow our instructions for testing your yogurt maker.


Q. I don’t have a yogurt maker, but I want to culture a thermophilic yogurt. What can I do?

A. There are a variety of methods for maintaining appropriate temperature for culturing thermophilic yogurt. Explanation of the different methods can be found in our article, How to Culture Yogurt Without a Yogurt Maker.


Q. My house is colder than 70ºF, how can I culture a mesophilic yogurt?

A. Many homes maintain temperatures that are cooler, especially in the winter. In our article, Maintaining Temperatures for Culturing Yogurt, find out how to keep your cultures the perfect culturing temperature.


Q. How do I make raw milk yogurt?

A. Please follow the instructions for the type of starter you are using.


Q. How can I make my yogurt thicker?

A. There are several ways to improve the thickness of the yogurt. Refer to the Thickening Homemade Yogurt article for information on a variety of thickening options.


Q. If I drain whey from my yogurt, how long can I store the whey in the refrigerator?

A. Whey will generally last about 6 months in the refrigerator. Always check the appearance and aroma. If it looks or smells bad, discard it.


Q. What do I do with whey?

A. Find lots of ideas in Ways to Use Whey.


Q. Can I make yogurt with lactose-free milk?

A. Maybe. Lactose-free milk isn’t actually lactose-free, but has lactase added, which makes the lactose easier to digest. Check the label and if you see lactase, the milk does contain lactose and may be used to culture yogurt. Avoid ultra-pasteurized milk for making yogurt.


Q. Can I use milk made from powdered milk to make yogurt?

A. Many customers have had success using a high quality powdered milk, such as Capramilk, for culturing yogurt. Other powdered milk brands are highly processed and may not perform well.

Q. How important is temperature when culturing yogurt?

A. The temperature for yogurt can vary within a certain range, but it is very important to stay within that range. Too warm and the bacteria will die. Too cool and the culturing will halt, and will likely not start again.


Q. How will I know when my yogurt has set?

A. Yogurt that has set will be more or less uniform in appearance: one solid mass. The yogurt should appear relatively smooth and should pull away from the side of the container when tipped. Sometimes a bit of whey will separate from the yogurt during the culturing process. This is completely normal.

Q. Why do I need to cool my yogurt at room temperature for 2 hours before refrigerating?

 A.  Giving your thermophilic yogurt some time at room temperature allows for a slower cooling process than placing it directly in the refrigerator.

Q. Why is store-bought yogurt thicker than homemade yogurt?

A. Store-bought yogurt generally contains thickeners. You can drain whey or add thickeners to homemade yogurt to achieve similar thickness. Details are in our article, How to Thicken Homemade Yogurt.


Q. When can I flavor my yogurt?

A. To avoid interfering with the culturing process, it is best to flavor after the culturing process is complete. This is most important when working with heirloom cultures. 


Q. Can I use my yogurt to revive another culture (like milk kefir, buttermilk, etc.)?

A. No, combining different cultures leads to competition between bacteria. The bacteria can kill each other, ending in an undesirable finished product.


Q. Are there differences when culturing yogurt at high altitudes?

A. Making yogurt at high altitudes causes it to set faster. Putting yogurt in to culture overnight might not be wise.


Q. How long will finished yogurt last in my refrigerator?

A. In the refrigerator (40° to 45°F): 7 days to maintain re-culturing viability; 2 weeks for edibility.


Yogurt Starter FAQ

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