Yogurt Starter FAQ

What ingredients are in your yogurt starters? 

Our Viili, Filmjolk, Matsoni, Piima, Greek, and Bulgarian yogurt starters are grown in our own facility using locally sourced pasteurized organic whole milk and live active cultures. The direct-set dairy cultures contain milk and live active cultures. The Vegetal Dairy-free Yogurt Starter contains rice maltodextrin (non-GMO) and live active bacteria.

What is the difference between different varieties of yogurt cultures?

The specific bacteria strains each have certain properties that will affect the finished yogurt. Some produce more lactic acid, making a more tart yogurt; some cause the milk proteins to coagulate in different configurations, making the finished yogurt gluier, or ropier, or more solid; some produce distinctive flavors, making the yogurt astringent, or cheesy.

Which bacteria strains do your yogurt starters contain?

• Traditional Flavored Direct-Set: Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Bifdobacterium longum, Bifdobacterium infanti

• Mild Flavored Direct-Set: Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus

• Viili: Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis biovar. diacetylactis, Leuconostoc mesenteroides subsp. cremoris

• Filmjölk: Lactococcus lactis, Leuconostoc mesenteroides

• Matsoni: L. lactis subsp. Cremoris, Acetobacter orientalis

• Piimä: S. lactis var. bollandicus, S. taette

• Greek: L. Bulgaricus, S. Thermophilus

• Bulgarian: L. Bulgaricus, S. Thermophilus

• Vegan Direct-Set: Bifidobacterium bifidum, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus delbrueckii subsp bulgaricus, Lactobacillus rhamnosus, Streptococcus thermophilus

• Kosher Traditional: Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus acidophilus, Bifidobacterium lactis

• Kosher Mild: Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus acidophilus, Bifidobacterium lactis

What is a direct-set yogurt starter and how is it different from a reusable yogurt starter?

Direct-set yogurt starters are one-time-use cultures. The powdered starter is added to milk and allowed to incubate producing yogurt. It may be possible to use some yogurt made with a direct-set starter to make a new batch of yogurt, but after a few batches, a new dose of direct-set starter is needed. With yogurt made from a reusable yogurt starter, a small amount of each batch is used to make the next batch. With proper care, a reusable yogurt starter can be perpetuated indefinitely. Reusable cultures must be cared for and perpetuated at least once a week to maintain their ability to culture milk.

Which starter is best for goat milk?

Any of our starters will work equally well for cow milk, goat milk, or any other mammal milk, and with raw milk or pasteurized milk.

If I want a thicker yogurt, can I use more starter?

Do not use more starter than recommended. If you use too much starter, the bacteria can become crowded, and may run out of food before the yogurt completes setting up. The result is a thinner yogurt, not a thicker one!

Can I mix starters together or add a probiotic capsule to get a different kind of yogurt?

Yogurt cultures are a carefully balanced combination of bacteria that will produce a particular kind of yogurt. If you mix different cultures or bacteria together, the bacteria may compete and weaken or die.

Once I start using the starter culture, how long will the bacteria stay viable enough for re-culturing?

We recommend that you use the yogurt from an heirloom culture within 5 to 7 days for re-culturing, to ensure the bacteria are strong enough to reproduce. You may be able to re-culture a yogurt from a direct-set starter a few times, but each batch will become thinner than the last, until you need a new direct-set starter.

How long will the starter culture stay good in the package?

Our freeze-dried cultures are shelf-stable for at least a month at room temperature, but we recommend refrigerating them if you are not going to use them right away, to extend their viability. In the refrigerator or freezer, the culture is stable for 9 months unopened, or 3 months after being opened and resealed.

If I’m going on vacation, how can I preserve my yogurt starter?

If you are using a reusable variety of yogurt starter, ideally you should make a new batch of yogurt every 7 days. Occasionally you may be able to stretch that period out by another day or two. If you will be gone longer than a week, the best solution is to find a friend who can care for your yogurt culture. You can also try freezing a small amount of 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, but no more than a few weeks.

Making Yogurt

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?

Yes, you can use any sort of milk for each batch of yogurt. Don’t forget, if you are using raw milk with a mesophilic yogurt, you will need to maintain a mother culture made with sterilized or pasteurized milk to preserve the viability of the culture.

Can I add cream to the milk to make a thicker yogurt?

The more milkfat (cream) there is in the milk, the thicker the yogurt will be. However, if you use whole cream, the bacteria may not remain viable enough to re-use for a second batch, since the culture uses milk sugar (lactose) for food. Whole cream has very little lactose. Adding half-and-half or cream to whole milk would result in a very rich, thick yogurt.

Can I make yogurt with lactose-free milk?

Lactose-free milk is usually made from cow milk with lactase added. Lactase is the enzyme missing in the gut of lactose-intolerant individuals. It breaks the lactose down into two simple sugars: glucose and galactose. The yogurt culture also consumes the lactose, and uses it to produce lactic acid, which makes the milk proteins coagulate. So if the milk did not have any lactose to start with, the yogurt culture would not work well. (The bacteria might consume the glucose for partial success in culturing.)

However, since the lactose IS broken down in the culturing process, there is not much lactose left in the finished yogurt even when you use regular milk. As a result, many lactose-intolerant individuals can enjoy yogurt. You might want to try a small amount of good quality plain yogurt, and if all goes well, start making your own. If you have concerns about your ability to tolerate yogurt, you should consult with your health-care practitioner.

How long does it take for a mesophilic culture to set up?

The amount of time it takes for a mesophilic (room-temperature) culture to set up properly depends on many things: The type of milk, how fresh the milk is, the temperature of the room, the freshness of the culture, the humidity of the environment, etc. A brand-new starter culture can set up as quickly as 10 hours, or it may take 48 hours. After you’ve made the starter culture, the subsequent batches can take anywhere from 10 to 24 hours.

How long does it take for a thermophilic culture to set up?

Ordinarily a thermophilic (heat-set) culture will take around 5 to 7 hours to set up, assuming it is culturing at a steady temperature of about 110°F. If the temperature is a little warmer or a little cooler, the time could vary.

How many batches of yogurt can I make with each packet of yogurt starter?

With a direct-set starter, you can generally make around eight 1- to 2-quart batches of yogurt per packet, or up to ten gallons if you make larger batches each time. Using proper care with our reusable yogurt starters, you can make an unlimited amount of yogurt by taking a small amount from each batch of yogurt to make the next batch. 

What’s up with the quantities of direct-set starter? The instructions say a box can make either 8 quarts or 20 gallons.

There are eight packets of direct-set yogurt in a box, and with thoseyou can make eight small batches of yogurt, or two very large batches, or anything in between. You must have at least 1/8 teaspoon of starter (one packet) for it to work properly in a quantity of milk, and you must have enough milk for the starter to grow and flourish.

The proportions of starter to milk that will successfully make yogurt are as follows:

1/8 teaspoon (1 packet): cultures 1 to 2 quarts at one time
1/4 teaspoon (2 packets): cultures 2 to 8 quarts at one time
1/2 teaspoon (4 packets): cultures 8 to 40 quarts at one time

How important is it to keep the right temperature for the yogurt as it’s culturing?

The temperature for yogurt can vary within a certain range, but it’s very important to stay within that range. Too warm, and the bacteria will die. Too cool, and the culturing will halt, and probably not start again. For a mesophilic culture, the range is 70° to 78°F, with about 72° to 76°F being ideal. For a thermophilic culture, the range is 105° to 115°F, with 110° to 112°F being ideal.

How will I know when my yogurt has set?

Yogurt that has set will be more or less uniform in appearance: one solid mass. There should not be a clear separation of curds and whey (white solid portion on top and clear liquid on the bottom). The yogurt should appear more or less smooth, not lumpy. If you gently tip the container, the yogurt should pull away from the side of the container. Sometimes a bit of whey will separate from the yogurt during the culturing process.

If I strain my yogurt, how long is the whey good for? What can I do with it?

Refrigerated, your whey should stay good for up to six months. You can use it to ferment vegetables like cabbage. The purpose of the whey is to get the lacto-fermentation to start up a little faster, For instance, most recipes for sauerkraut recommend about four tablespoons of whey to a quart of cabbage. You can also add whey to smoothies for extra protein, either as liquid, or frozen in ice cubes.

Yogurt Troubleshooting

I followed all the instructions exactly, and my yogurt did not turn out. What did I do wrong?

We get this question a lot! There are three possibilities: either you misunderstood a step or two in the instructions, or the milk was not culturable, or the starter you received was not working properly in the first place. Be sure to rule out the first two possibilities before assuming the last. Our customer support representatives can help you figure it out. The most common errors are:
 

The culturing temperature was not right. You can test the temperature of the environment you’re culturing in, whether it’s a yogurt maker or a countertop, by preparing some water the same way you would prepare the milk for the yogurt, and taking the temperature of the water at intervals throughout the culturing time.

You used the wrong quantity of milk, or the wrong quantity of culture. The activation batch (mother culture) is only one cup. It’s important to let the culture come back to operating strength in this small amount of milk before trying to culture a larger batch. Also, you must use at least 1/8 teaspoon of culture, as a smaller amount may not have enough strength to work. Do not use too much culture for the amount of milk. A culture that is crowded can’t work properly, and can weaken or die before it finishes setting up the yogurt.

You just didn’t wait long enough. A new yogurt culture can take longer than you expect to set up properly. Be sure to allow enough time for the culture to fully awaken and start working.

The milk was not culturable. Milk that is not “clean” enough can present competition for the yogurt culture. This would include raw milk that is more than a few days old, or that has not been chilled immediately after milking. It can also include pasteurized milk that is not very fresh and has not been properly heated. On the other hand, milk that is “too clean,” such as ultra-pasteurized milk, or milk that has been heated by microwave, may be too sterile for the yogurt culture to use as nourishment.

Why did my yogurt separate into curds and whey?

Separation is generally a sign that the yogurt has cultured too quickly or too long. It may indicate that the culture has died. Try mixing the curds and whey together, then make a new batch, being careful to control the time and temperature. If that fails to produce a good yogurt, then the culture has died and you will need to replace it.

Where can I find more troubleshooting information?

Click here for Yogurt-Making Troubleshooting FAQs.

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