Yogurt is created when certain safe, edible bacteria grow in warm milk. To make yogurt, you must choose the right starter culture that contains active live bacterial cultures.
You can also use a bit of yogurt made in an earlier batch. Cover the yogurt and keep it in a warm place. This will encourage wanted bacteria to grow and keep unwanted bacteria away.
You can refrigerate the yogurt following incubation.
In this guide, we will discuss how to select the best yogurt starter culture.
What is a yogurt starter?
Microbes sometimes create delicious food and that is what a yogurt starter is all about.
Heat-loving bacteria such as Lactobacillus acidophilus eat away at the sugars in the milk and quickly grow at the right temperatures while crowding out unwanted bacteria.
As they break down the milk sugars, yogurt bacteria produce lactic acid which imparts a delicious, tangy flavor to the milk. Proteins in the milk also unravel and get chopped into smaller pieces during the yogurt making process.
This imparts a colloidal, gel-like consistency to yogurt which is why yogurt thickens as it sets. And since the milk proteins are broken down, they get easier to digest.
Can you make a yogurt starter culture at home?
Yes, it is very easy to make yogurt starter culture at home. Simply save a couple of tablespoons of yogurt you make at home and use it to start your next batch of delicious homemade yogurt.
Reasons why you should make your yogurt starter culture at home
You can always buy your yogurt culture from the store but once you master the art of making yogurt at home, you’d never go back to store-bought yogurt starters for the following reasons:
Store-bought yogurt is often filled with chemicals and preservatives. With a homemade starter, you are assured that your yogurt is free from unwanted ingredients. Homemade yogurt also has a great taste; it has the right amount of sweetness and tartness and you won’t even have to add sugar to it.
Once you start making your yogurt starter culture at home, you can experiment with a variety of flavors and save tons of money. Add fruits, natural sweeteners like honey or agave, and make a range of smoothies each morning with your healthy and tasty yogurt.
Great for your gut health
There is no doubt that we all need to eat probiotic foods. The very meaning of the word probiotic is ‘for life’. Thus, yogurt is a life-supporting food that can improve wellbeing, boost immunity, and improve digestion.
Recipe to make yogurt starter culture at home
- Rinse out a saucepan with water to remove contaminants and unwanted bacteria that can impede the growth of good or yogurt-producing bacteria.
- Add milk to the pan and set it on the stove on medium flame to heat. You can also pour in a quarter cup of heavy cream or a couple of tablespoons of dry milk powder in the pan. This will give you a thicker yogurt.
- Keep stirring as the milk heats up. Use a thermometer to note the temperature. Avoid boiling the milk and make sure that it does not stick to the bottom or the sides which can cause it to burn. Once the temperature reaches around 180°F 82°C, switch off the heat and remove the pan from the flame.
- Cool the milk to 110°F. This is about 43°C. This temperature is ideal for good bacteria to develop.
- Take 4 tablespoons of starter culture or plain yogurt. You can use homemade yogurt or simply use store-bought plain low-fat or whole-milk yogurt. Add this to the warm milk.
- Stir or whisk the milk well. Cover the pan and place thick towels around it. This will prevent the heat from escaping.
- Depending on the ambient temperature, place the milk in a warm place and leave it undisturbed for 6-8 hours.
- In winters or very cold climates, you can use your oven to prepare the yogurt. Pre-heat the oven to about 120°F and then switch it off. Place the inoculated warm milk inside the oven and keep the light on for added warmth. It is essential to leave the yogurt undisturbed for at least 6 hours.
- After the yogurt has set, place it in the refrigerator. You can consume it immediately and leave a bit for making your next batch of yogurt.
Keeping the temperature
When making a yogurt starter culture, it is extremely important to keep the temperature up to 110°F. Apart from an oven or microwave, you can use the following things or appliances:
- Crockpot – Place foam on the bottom of the crockpot and place your yogurt container inside the crock. Place one more foam layer on top and then seal the crock.
- Dehydrator – Food dehydrator on a low setting can also be used for storing your yogurt container. Just keep the dehydrator on its lowest setting.
- Hot water bath – Make a hot water bath (not too hot or boiling) and place the container in it. You will have to keep adding hot or warm water to maintain the temperature to about 110°F.
- Heating pads – Test the temperature of the pad first to ensure that it isn’t too hot otherwise it could spoil your batch.
- Yogurt makers – These are designed to keep the yogurt jars at 110°F.
Different types of yogurt starter cultures
Remember that different yogurt cultures will produce different textures and tastes in yogurt. The general function of any starter culture is to ferment the milk from a pH of 6.4 to 6.7 to a pH of about 3.8 to 4.2.
Starters are available in liquid, ultra-frozen, or dehydrated forms
- The liquid form is supplied in sterile, reconstituted skim milk. It can keep in the refrigerator at a temperature of about 8°C for 1-2 weeks.
- A frozen culture can be maintained at -30°C or -40°C for about 6 months. Commercially, frozen starter cultures for yogurt and cheese can also be maintained in liquid nitrogen.
- Dried or dehydrated cultures are vacuum-packed, frozen, freeze-dried, or concentrated freeze-dried and can last for 6 months to a year.
Starters contain different bacterial strains
- Pure cultures – These contain a single strain of bacteria.
- Mixed cultures – These are also called co-cultures. They contain a defined mixture of pure cultures which can be different types of bacteria. A mixed culture consists of natural starters and undefined mixtures of different strains of species of lactic acid bacteria.
Starter cultures are also divided in terms of temperature growth characteristics
- Mesophilic – The optimum growth range for mesophilic bacteria in this type of yogurt starter culture is 20 to 45°C.
- Thermophilic – The term thermophilic is reserved for microorganisms that are most active between 35 to 45°C.
Commercial yogurt starter cultures can employ any of the following microorganisms:
- Lactobacillus bulgaricus
- Bifidobacterium lactis
- Streptococcus thermophilus
- Streptococcus salivarius
- Lactobacillus delbruecii
- Lactobacillus helveticus
Which is the best yogurt starter?
There are two possible choices for you when it comes to picking the best yogurt starter culture.
Your first choice is to go in for powdered yogurt starter which you can buy online. This is ideal for the novice yogurt-makers who are experimenting with yogurt making for the first time.
The packets come with instructions and you simply have to follow them to make great-tasting yogurt. Dry starters work very well and they are portable as well, should you need to carry them with you when you travel.
Dry starters may not be enough if you want to make several batches of yogurt. In other words, you cannot save a bit of the yogurt from one batch to start the next or subsequent batches as after a batch or two they may lose their strength.
A much easier and more affordable option is to buy fresh plain yogurt. If it is from a good brand, it is likely to contain many active, live cultures that can ferment your warm milk easily.
Check the labels for the terms ‘live cultures’ or ‘active cultures’. This will show you if the yogurt contains potent and strong bacterial strains that can ferment several batches of your milk.
Avoid using fruit-flavored or frozen or sweetened yogurts to inoculate warm milk. These can affect the taste of your end product. Plain, sour yogurt works best as it gives a great taste to yogurt (provided you follow all instructions well) and it will give you a source of perpetual culture that you can use over and over.
You need at least 1/8th to 1/6th as much yogurt starter as milk. For example, you can use one 6-ounce serving or one container of yogurt to make 6-8 servings of yogurt. The higher the proportion of yogurt starter (with the exception of dried cultures), the faster the fermentation.
How to know if your yogurt starter contains live cultures
As stated above, you must read the labels of the plain/regular yogurt. Look for the terms ‘live cultures’ or ‘active cultures’. This will show you if your yogurt starter contains potent and strong bacterial strains that can ferment several batches of your milk.
A majority of commercial yogurt brands contain Lactobacillus acidophilus, Lactococcus thermophilus, and lactobacillus bulgaricus. However, thanks to modern research, scientists also recommend other strains like L.casei, L.paracasei, L.reuteri, L. rhamnosus, L.plantarum, and Bifidobacterium. There are several other probiotic strains as well.
Each of these strains is known to boost immunity, improve gut health, and enhance digestion.
So you can readily buy yogurt containing these strains and that should make a healthy starter culture. Note that not all these strains of friendly bacteria will culture at the same temperature and that many manufacturers often add friendly bacteria after the yogurt is made.
But at least you can be assured that a broad spectrum of beneficial or probiotic bacteria are present in your culture and hopefully, at least a few of them will make it through and colonize your yogurt batch.
Where should I buy my starter culture from?
For starter cultures, simply purchase plain yogurt that states ‘live’ or ‘active’ cultures on its labels. Avoid fruit or frozen yogurts as they contain undesirable microorganisms as well as sugar. These undesirable microorganisms may out-compete the desirable bacteria.
You can safely use cow’s milk yogurt to inoculate goat milk and vice-a-versa. What is important is ‘live’ and ‘active’ strains.
If you use store-bought yogurt for starter, make sure you use freshly opened container to ensure that you only inoculate with desirable bacteria. Partially used, opened container left open on the breakfast table or that has been eaten with a not-so-clean spoon is a strict no-no when making yogurt.
Choose a brand of yogurt you like. Some yogurts are tangier, others are a bit mellow. If you use tart and tangy store-bought yogurt, then your batch will be tangy too. Also, make it a point to check the expiration date of your yogurt container because even an unopened container can become tangy over time.
If you use dried culture brought online, follow the label instructions.
Promptly freeze unwanted culture and use it up within a few months. Most remain viable for up to 6 months. In the case of dried cultures, more culture may not necessarily mean faster fermentation. In fact; the opposite is more likely as the milk may not contain enough lactose to feed all of the bacteria. They may even die off before they coagulate the milk.
- LIke your yogurt sweeter and thicker... then this is the culture for you to make your own.
- Freeze-dried concentrated lactic starter to make Yogurt
- 1/16th tsp to make 2 quarts of wonderful yogurt
- Contains one Tsp to make about 8 gallons, but make more by using tbsp of yogurt to innoculate the next batch
Using homemade yogurt as a starter culture to make yogurt has a lot of appeal. It costs next to nothing and gives you immense satisfaction of keeping the starter going. Naturally, there are challenges in yogurt making and you should be aware of them.
Yogurt cultures evolve since the bacteria in them change and die off over time. So, over time, you may need to change your culture as you could find your yogurt becoming tangier, stringier, thinner, or less stable. In such cases, you may find that you have to buy store-bought yogurt starter or dried yogurt starter.
To maintain the strength, purity, and vigor of your homemade starter batch, I recommend that you make yogurt at least once a week at home. Fresh homemade yogurt that is less than a week old is bound to contain the right balance of bacteria and can serve as the perfect yogurt starter.