How to Make Bulgarian Yogurt
How to Make Bulgarian Yogurt at Home: Step by Step Guide
The Short Answer
To make Bulgarian yogurt at home, heat 1 litre of whole milk to 82°C, cool to 42°C, then stir in your live Bulgarian yogurt starter culture. Incubate at 42°C for 3 hours, then reduce to 35°C for a further 5 to 7 hours. This two stage temperature method is what gives Bulgarian yogurt its distinctive smooth, creamy texture and balanced tang. Once set, refrigerate for at least 2 hours before eating.
In This Guide
Bulgarian yogurt is widely considered to be one of the finest styles of yogurt in the world. It is made using two specific bacterial strains, Lactobacillus bulgaricus and Streptococcus thermophilus, that work together to produce a smooth, creamy yogurt with a clean, balanced tang that is noticeably different from standard commercial yogurt.
What sets Bulgarian yogurt apart from Greek yogurt is the texture and the method. Bulgarian yogurt is not strained, it achieves its creaminess through a precise two stage fermentation temperature, starting high and dropping lower partway through. Once you understand this technique, making consistent, authentic Bulgarian yogurt at home becomes straightforward.
What Makes Bulgarian Yogurt Different
The Culture
Bulgarian yogurt uses two specific thermophilic strains, Lactobacillus bulgaricus and Streptococcus thermophilus, that work together in a symbiotic relationship. Neither strain produces the same result on its own. Together they create a flavour and texture profile unique to Bulgarian style yogurt.
The Texture
Unlike Greek yogurt which is thickened by straining, Bulgarian yogurt achieves its creamy, custard-like texture entirely through the fermentation process and the temperature swing technique. No straining required.
The Flavour
Bulgarian yogurt has a clean, milky tang that is sharper than Greek yogurt but not overwhelming. It is versatile enough to eat plain, use in cooking, or blend into smoothies and dips.
The Heirloom Nature
A Bulgarian yogurt culture can be reused indefinitely by using a small amount of each batch to start the next. With proper care your initial starter culture will keep producing fresh yogurt for years.
What You Need to Make Bulgarian Yogurt
Equipment and Ingredients
- 1 litre of whole milk, organic where possible for best results
- Bulgarian yogurt starter culture, either our freeze dried Bulgarian culture for a first batch or 1 tablespoon of your previous batch for reculturing
- A food thermometer, essential for the two stage temperature method
- A heavy bottomed saucepan
- A clean glass jar or ceramic bowl with a lid, for incubation
- A yogurt maker, instant pot, warm oven or insulated flask, to maintain incubation temperature
The Temperature Guide: Why the Two Stage Method Works
The temperature swing is the single most important technique in making authentic Bulgarian yogurt. It is what prevents the yogurt from becoming overly sour and what produces the smooth, custard-like consistency that makes Bulgarian yogurt distinctive.
Heat Milk to 82°C
Scalding the milk denatures the whey proteins, which allows them to bond together and form the structure that gives the yogurt its thick, smooth set. This step is mandatory for a proper Bulgarian yogurt texture.
Cool to 42°C, Add Culture
Once cooled to 42°C, stir in your starter culture for 1 to 2 minutes until fully dispersed. Never add the culture above 45°C as this will kill the live bacteria. Stir gently to ensure even distribution throughout the milk.
Incubate at 42°C for 3 Hours
The first stage at 42°C activates the Lactobacillus bulgaricus strain, which begins producing lactic acid and developing the characteristic Bulgarian tang. This phase builds the flavour foundation of the yogurt.
Drop to 35°C for 5 to 7 Hours
Dropping the temperature to 35°C for the remaining incubation time slows the acidification process and allows the Streptococcus thermophilus strain to complete the set. This produces a smoother, creamier texture and prevents the yogurt from becoming overly sour.
NutriBrew Tip: If you want a milder, less tangy Bulgarian yogurt, extend the lower temperature phase to 8 hours instead of 5 to 7. The longer and cooler the second phase, the smoother and less acidic the finished yogurt will be.
Step by Step: How to Make Bulgarian Yogurt
The Full Method
Step 1: Heat the milk
Pour 1 litre of whole milk into a heavy bottomed saucepan and heat slowly over a medium heat, stirring occasionally to prevent scorching. Bring to at least 82°C. Use a thermometer to confirm the temperature.
Step 2: Cool to 42°C
Remove from heat and allow the milk to cool to 42°C. You can speed this up by placing the saucepan in a bowl of cold water and stirring gently. Check with your thermometer and do not add the culture until the temperature is at or below 42°C.
Step 3: Add your starter culture
Stir in your Bulgarian yogurt starter culture gently for 1 to 2 minutes until fully dissolved and evenly dispersed throughout the milk. If using a freeze dried culture, follow the packet instructions for quantity. If reculturing from a previous batch, use 1 tablespoon per litre.
Step 4: First incubation at 42°C for 3 hours
Pour the inoculated milk into your incubation vessel and maintain at 42°C for 3 hours. Do not disturb or stir the yogurt during incubation as this can break the set.
Step 5: Drop to 35°C for 5 to 7 hours
After 3 hours, reduce the incubation temperature to 35°C and continue for a further 5 to 7 hours. This is the temperature swing that gives Bulgarian yogurt its distinctive smooth and creamy finish.
Step 6: Refrigerate before eating
Once incubation is complete, move the yogurt to the fridge for at least 2 hours before eating. This allows the protein structure to firm up fully and the flavour to settle. The yogurt will continue to develop over the first 24 hours in the fridge.
Incubation Methods for the Two Stage Temperature
Managing two different temperatures during incubation is easier than it sounds. Here are the most practical approaches for an Irish home kitchen.
Yogurt Maker
Set to 42°C for the first 3 hours, then adjust to 35°C for the remaining time. The most hands off and reliable option for the two stage method.
Instant Pot
Use the yogurt setting for the first 3 hours at 42°C. After 3 hours, switch off and leave the lid on. The residual warmth will naturally bring the temperature down toward 35°C for the second phase.
Warm Oven
Preheat oven to 50°C, turn off, place your yogurt jar inside. After 3 hours, open the oven door slightly to allow the temperature to drop toward 35°C for the second phase. Check with a thermometer.
Insulated Flask
Pour into a preheated wide mouth flask and seal. After 3 hours transfer to a slightly cooler insulated container or wrap in a towel to allow the temperature to drop naturally for the second phase.
How to Recultue Bulgarian Yogurt
Bulgarian yogurt is a true heirloom culture. Using a small amount of each finished batch to start the next means your initial purchase keeps producing indefinitely.
Reculturing Rules
How much to use: 1 tablespoon of your previous batch per 1 litre of new milk.
Freshness window: Use yogurt no more than 7 days old. Beyond this the bacterial strains begin to weaken and the yogurt will become progressively thinner over successive batches.
Keep a backup: Every 4 to 5 batches, freeze a small portion of fresh yogurt as a safety net. If a batch fails or the culture weakens, you can restart from frozen rather than purchasing a new starter.
When to start fresh: If the texture becomes noticeably thinner over several consecutive batches despite following the correct method, start fresh from a new culture rather than continuing to recultue from a weakened one.
Bulgarian Yogurt Troubleshooting
Yogurt is Thin or Runny
Cause: Milk not scalded to 82°C or culture added while milk was too hot
Fix: Always scald to at least 82°C and cool to exactly 42°C before adding culture. Use a thermometer.
Yogurt is Too Sour
Cause: First phase too long or temperature swing not applied
Fix: Keep the 42°C phase to no more than 3 hours and make sure you drop to 35°C for the second phase. Extending the lower temperature phase also reduces sourness.
Yogurt Did Not Set
Cause: Culture killed by heat, incubation too cool, or culture past its best
Fix: Check temperature with a thermometer at each stage. If reculturing, use yogurt no older than 7 days.
Grainy or Lumpy Texture
Cause: Milk heated too quickly or stirred during incubation
Fix: Heat milk slowly and do not stir or move the yogurt once incubation has begun. Disturbance breaks the protein mesh as it forms.
Liquid on Top After Setting
Cause: Normal whey separation
Fix: Stir it back in before eating. This is completely normal and does not affect quality. Let the yogurt cool at room temperature for 30 minutes before refrigerating to reduce separation.
Getting Thinner Over Batches
Cause: Culture weakening from reculturing too old yogurt
Fix: Always recultue from yogurt no older than 7 days. If still declining, start fresh from a frozen backup or a new culture.
Frequently Asked Questions About Bulgarian Yogurt
What is the difference between Bulgarian yogurt and Greek yogurt?
The main differences are texture, method and culture. Bulgarian yogurt is not strained and achieves its creamy consistency through the two stage temperature fermentation process. Greek yogurt is strained to remove whey, making it thicker and higher in protein. Bulgarian yogurt tends to have a slightly sharper, cleaner tang, while Greek yogurt is richer and denser. Both use thermophilic cultures but the specific bacterial strains and methods differ. Our Greek yogurt guide covers the comparison in more detail.
Do I need a yogurt maker to make Bulgarian yogurt?
No, but it makes the two stage temperature method considerably easier. A warm oven, instant pot, wide mouth insulated flask or even a bowl wrapped in towels can all maintain the right temperature. The key is being able to monitor and adjust the temperature at the 3 hour mark when you need to drop from 42°C to 35°C. A thermometer is more important than any specific piece of equipment.
How long does homemade Bulgarian yogurt last?
Stored in a sealed container in the fridge, homemade Bulgarian yogurt will keep well for up to 2 weeks. It becomes slightly more tart over time as fermentation continues slowly in the cold, but it remains safe and good to eat throughout. Always use a clean spoon when serving to avoid introducing bacteria that could shorten shelf life.
Can I use Bulgarian yogurt the same way as Greek yogurt?
Yes, in most recipes. Bulgarian yogurt works well in smoothies, dips, dressings, marinades, overnight oats and baking. It is slightly thinner than strained Greek yogurt, so for recipes where texture matters, such as tzatziki or thick dips, you may want to strain it briefly through muslin cloth to thicken it up. For everything else it is a direct substitute.
Is Bulgarian yogurt the same as regular yogurt?
No. Most commercial yogurts use a limited number of bacterial strains and are often thickened with additives. Bulgarian yogurt uses the specific combination of Lactobacillus bulgaricus and Streptococcus thermophilus that gives it its distinctive flavour and texture. It is also made fresh at home with no additives, stabilisers or preservatives, which makes it noticeably different from anything you can buy in a shop.
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