Jars of yogurt incubating in a warm water bath

Yogurt Incubation Temperature by Strain: The Master Reference

ByCraig Brockie Last updated

What this table shows

The right incubation temperature depends on which bacteria are doing the work. Classic yogurt bacteria are heat lovers. Most probiotic species came from the human gut and grow near body temperature. A few cheese and buttermilk cultures prefer a cool kitchen.

The table pairs two kinds of numbers. The lab columns come from BacDive, the bacterial database run by the DSMZ culture collection in Germany, for each species’ type strain (the reference strain that defines the species). The last column is the home setting used in our individual culture guides. Lab growth temperature is not the same as the best yogurt temperature, as the notes below explain.

Yogurt incubation temperature by strain

GroupCultureLab growth temperature (type strain)Growth range reportedTypical home setting
Thermophilic (heat-loving)Streptococcus thermophilus37 to 42°C (99 to 108°F)25 to 45°C; none at 10°C110 to 115°F, about 8 h
ThermophilicLactobacillus delbrueckii subsp. bulgaricus37°C (99°F)30 to 45°C110 to 115°F, about 8 h
ThermophilicLactobacillus helveticus37°C (99°F)30 to 45°C108 to 112°F, about 12 h
ThermophilicLactobacillus acidophilus30 to 37°C (86 to 99°F)22 to 45°C108 to 112°F, about 12 h
Body temperatureLacticaseibacillus rhamnosus (GG is one strain)37°C (99°F)15 to 45°C108 to 110°F, about 12 h
Body temperatureLactobacillus gasseri37°C (99°F)37 to 45°C100°F, up to 36 h
Body temperatureLimosilactobacillus reuteri37°C (99°F)30 to 45°Cabout 99°F, about 24 h (see note)
Body temperatureLacticaseibacillus casei30 to 37°C (86 to 99°F)15 to 45°C98 to 104°F, about 24 h
Body temperatureLacticaseibacillus paracasei30 to 37°C (86 to 99°F)15 to 37°C; none at 45°C98 to 104°F, about 24 h
Body temperatureLigilactobacillus salivarius37°C (99°F)22 to 45°C98 to 104°F, about 24 h
Body temperatureLimosilactobacillus fermentum37°C (99°F)15 to 45°C98 to 104°F, about 24 h
Body temperatureBifidobacterium animalis subsp. lactis37°C (99°F)not listed100 to 105°F, about 24 h
Body temperatureBifidobacterium longum37°C (99°F)not listed100 to 105°F, about 24 h
Body temperatureBifidobacterium bifidum37°C (99°F)not listed100 to 105°F, about 24 h
Body temperatureBifidobacterium breve37°C (99°F)not listed100 to 105°F, about 24 h
Warm roomLactiplantibacillus plantarum30 to 37°C (86 to 99°F)15 to 30°C in one test; none at 45°C86 to 95°F, about 24 h
Mesophilic (room temperature)Lactococcus lactis30°C (86°F)30 to 37°C; none at 10 or 41°C72 to 77°F, about 12 h
MesophilicLeuconostoc mesenteroides25 to 37°C (77 to 99°F)15 to 37°C; none at 45°C72 to 77°F, about 12 h
Spore formerHeyndrickxia (Bacillus) coagulans37 to 40°C (99 to 104°F)22 to 55°C; maximum 60°C115 to 122°F, up to 36 h

Column sources: the lab temperature and growth range come from each species’ BacDive type-strain record, which compiles data from culture collections (linked in the table). Growth range means temperatures at which a collection reported positive growth in lab broth. Home settings come from our culture guides, except L. reuteri, which follows the 37°C, 24-hour milk study below. Commercial strains, including LGG and branded probiotics, can differ from the type strain.

How to read the table

Plain yogurt maker with glass jars on a counter

The lab number is a starting point

Culture collections grow most gut bacteria at 37°C because it is a standard lab setting, not because it is the best yogurt temperature. In milk, the best temperature for making acid can sit above the best temperature for growth. A study of 9 S. thermophilus and 10 L. bulgaricus strains found growth optimums of 35 to 42°C and 43 to 46°C, and S. thermophilus made acid fastest 2 to 8°C above its growth optimum (Radke-Mitchell and Sandine, Journal of Dairy Science, 1986). That is part of why extension guides incubate ordinary yogurt warmer than body temperature.

Classic yogurt: 100 to 115°F

Extension advice for ordinary yogurt clusters in a narrow band: 108 to 115°F for 6 to 10 hours (University of Illinois Extension), 110°F plus or minus 5°F for 4 to 7 hours (University of Alaska Fairbanks Extension), or 100 to 110°F for 4 to 8 hours (University of Missouri Extension). Warmer is faster: milk fermented with both yogurt bacteria at 42°C (108°F) finished significantly sooner than at 37°C (99°F) and scored higher with tasters (Wu et al., Journal of Dairy Science, 2025). For more on timing, see how long to incubate yogurt.

Probiotic species: lower and longer

Body-temperature species usually work slowly in plain milk. In one lab study, L. acidophilus, L. rhamnosus GG, L. reuteri and B. animalis BB-12 were grown alone at 37°C in UHT milk with a little added tryptone or fructose to help them along. They took the milk from pH 6.7 to between 3.9 and 4.4 in 24 hours (Østlie et al., International Journal of Food Microbiology, 2003). That is why home methods for these species, such as our L. gasseri and L. reuteri guides, run cooler and longer than ordinary yogurt.

Cool and hot outliers

Lactococcus lactis, the main cheese culture, has its growth optimum around 30°C (86°F) (Chen et al., Scientific Reports, 2015), and BacDive records no growth for its type strain at 41°C (106°F).

Heyndrickxia coagulans, still sold as Bacillus coagulans, sits at the other end. A growth model for strain DSM 1 estimated an optimum of about 52.9°C (127°F) and a maximum near 59.4°C (139°F) in lab broth (Misiou et al., Food Research International, 2021). Our B. coagulans GBI-30 guide uses 115 to 122°F, below that optimum.

Mixing cultures

When you combine a probiotic with ordinary yogurt bacteria, set the incubator for the culture that has to set the milk, then keep it within the probiotic’s growth range. For example, 108 to 112°F suits S. thermophilus and stays inside the 22 to 45°C (72 to 113°F) range listed for L. acidophilus. The probiotic yeast Saccharomyces boulardii does not set milk on its own; see our S. boulardii guide.

Methodology and limits

  • Lab temperatures come from culture-collection records for one reference strain per species, grown in lab broth, not milk.
  • Home settings are practical choices from our guides, not optimums we measured. We did not test these cultures.
  • Strains within a species vary. If your starter’s maker lists a temperature, follow it.
  • Your incubator matters as much as the number. Many units drift a few degrees; see yogurt maker temperature drift.

Related topics

Sources

Craig Brockie is the founder of Ultimate Health Solutions, the company behind Ultimate Gut, and the author of Ultimate Health, The Ultimate Gut Health Guide and The Unlimited Probiotics Guide. After injuries and chronic health problems in his twenties that conventional care didn’t resolve, he began researching health on his own and has studied natural health for 30 years. He is not a medical professional, and his articles are general information, not medical advice.

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