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Sour yogurt has been around for centuries, although it has not always been categorized as sour yogurt. It is yogurt which has a higher than normal amount of acid in it. The acid can be from natural fermentation processes or by adding acid to the yogurt after incubation. It has many uses from savory sauces to sweet and tangy desserts.
There are also many ways to make sour yogurt which include what I would call instant cheats like adding ascorbic or acetic acid to store bought yogurt to making it from scratch using a live yogurt culture and milk. Here are answers to some of the frequently asked questions about sour yogurt along with some great ways to use it in your daily cooking.
Why does homemade yogurt become sour?
Once you have been making yogurt for a while you may get the experience of adding some of your latest batch to a bowl of fruit or into a smoothie only to discover it is overly sour tasting. When you smell it it seems fine, maybe a little more tart smelling than usual but nothing like how it tastes.
Yogurt gets sour when lactic acid bacteria in the culture consumes most of the lactose in the milk. This reduces sweetness and increases the amount of lactic acid found in the yogurt. This can happen due to using too much starter, incubating too long or using too high an incubation temperature.
Yogurt culture is a collection of living bacteria which have very specific environmental needs such as temperature, starter-milk ratio, species in the culture, length of time the milk is incubated, how long the milk was pasteurized and cleaning procedures.
When making yogurt at home it is difficult to be able to control all these conditions and as a result your yogurt will have some variation. It may have more or less lactose remaining giving it some variation in tanginess.
For a complete explanation of why your homemade yogurt gets too sour and how to control how sour your yogurt gets check out “The three reasons why your yogurt becomes sour”.
Is it safe to eat sour yogurt
The first time you make yogurt which has become overly sour the first question which pops into your mind is probably is it still safe to eat? The fear of getting food poisoning and becoming violently ill by eating spoiled food is overwhelming. This fear is baseless when it comes to fermented foods, including yogurt. If you have followed the recommendations for fermenting foods safely they will be safer than their fresh counterparts.
Sour yogurt has a high lactic acid content lowering the pH of the yogurt more than normal. This acts as a preservative, protecting the yogurt from spoilage bacteria like clostridium botulinum. Most spoilage microorganisms thrive in a basic environment rather than acidic conditions of sour yogurt.
Although it can be unpleasant to eat overly sour yogurt (unless you like the taste of sour things) it is perfectly safe to eat. The WHO (world health organization) states that fermented foods which have a pH below 4.0 are generally safe to eat. This is because bacteria like clostridium botulinum cannot thrive in acidic environments. Many molds are also sensitive to acidic conditions which extends the length of time your homemade yogurt can be stored.
What are the benefits of sour yogurt
In years past yogurt was dubbed a health food, it was said to improve digestion, help prevent flu or shorten its infection, improve constipation and help prevent colds. Although these claims were exaggerated to some degree to improve the sale of certain brands of yogurt, most of the advertised benefits had some basis in truth.
The health benefits of yogurt stem from the lactic acid bacteria used to ferment the milk. Lactic acid bacteria use the lactose to grow and produce lactic acid as a byproduct of their respiration. As the lactic acid bacteria population increases their effect on digestion is greater.
Sour yogurt has a higher bacteria count due to the culture having had a longer period of time to multiply its population. Lactic acid bacteria can double its population in under an hour depending on the incubation temperature, the pH of the milk and the strength of the culture so by incubating yogurt for 24-36 hours the population of the lactic acid bacteria is greater than yogurt incubated for 6-12 hours.
Does sour yogurt improve digestion
Sour yogurt can have a positive effect on the digestive system depending on the individual, their current state and food sensitivities. It does this by adding live lactic acid bacteria into the digestive tract. Live lactic acid bacteria does survive the acidic conditions of the stomach, something which was in doubt in the past, the surviving lactic acid bacteria consume some of the sugar it finds available in the digestive tract and produce beneficial compounds which can improve digestion.
Although it was thought that the surviving lactic acid bacteria can take up permanent residency in the digestive system, this has been found to be incorrect. The lactic acid bacteria which are found in yogurt rarely persist in the gut but instead they are transient. This is not a bad thing, it just means that if you want the benefits of these bacterial species you need to consume yogurt regularly.
Does sour yogurt reduce the chance and shorten the duration of a flu
There are some studies which suggest that regular consumption of a high quality yogurt can lower the chances of getting a cold or flu and can shorten the duration of the sickness if you do get sick. Again this requires regular use of yogurt to maintain the benefits
Besides the health benefits there are other benefits of sour yogurt. Sour yogurt will last longer than regular yogurt, improve the flavor of savory dishes and sauces and provide an added boost to the rising agent in quickbread baking. The additional lactic acid and lower sugar content in sour yogurt provides savory recipes with an added tang.
Is greek yogurt and sour yogurt the same
Greek yogurt is another product which has become quite popular in recent years. It has a thick creamy texture which provides a great base for dips, sauces and just eaten plain or on a bowl of fruit. It is made by adding an additional step to the yogurt making process which is the removal of some of the whey from the yogurt to make it thicker.
Greek yogurt and sour yogurt are not the same. The process for making sour yogurt requires extending the incubation time, adding additional starter and/or adjusting the incubation temperature, whereas making Greek yogurt is done by removing some of the whey from the yogurt.
Greek yogurt can be made using sour yogurt. This will make for a very tangy creamy greek yogurt which would be especially good for savory sauces and dips. The thick texture of the yogurt will help it to stick to whatever food it is poured over or dipped into and the tangy flavor will accentuate the spices.
What can I do with sour yogurt
As mentioned above there are many uses for sour yogurt. Here is a list of the 10 ways I use sour yogurt most often. It includes everything from making tangy cream cheese to using it for tzatziki.
- Tangy cream cheese
This is an easy recipe and is the base for several of the following recipes including ice cream, cheesecake and hard yogurt cheese. It is the same process used to make Greek yogurt with an extended draining time. Check out this recipe for step by step instructions.
- Tzatziki
A classic greek dip used for veggies and bread or as a spread in sandwiches. Tzatziki made with sour yogurt has an added tang which helps to bring out the dill and lemon flavors. Use it in rich dishes to clear the palate between bites and courses. Use it as condiment wherever you feel the need for a fresh tangy flavor.
- Creamy mustard dressing
The tangy flavor of sour yogurt provides the acidic flavor which vinegar usually adds to a salad dressing. This creamy mustard dressing uses our yogurt, lacto-fermented mustard (recipe here) and a little honey. It is great on mixed salad greens or used in sandwiches.
- Dilly veggie dip
Dilly dip is a popular addition to any get together. It has an element of healthy eating built into it as it goes well with vegetable sticks as well as crackers and chips. It is simple to make, requiring only dill, lemon or lime and salt and pepper to taste. A good dilly dip should be made the day before use to allow the flavors to fully develop but it can also be made short notice when necessary.
- Grain free waffles or pancakes
When making grain free waffles or pancakes the challenge is that the “flour” is really heavy which prevents them from rising. When sour yogurt is used the extra lactic acid reacts with the baking powder more completely causing the batter to rise more.
- Morning smoothie
The morning smoothie can be made with a variety of ingredients. This one uses any type of fruit, kombucha, sour yogurt and a little honey to cut the tartness of the yogurt and the sweetness of the fruit.
- Turmeric health smoothie
Turmeric has been used for centuries to reduce inflammation, improve __ and as a flavor agent in a wide variety of recipes. Scientists have found that the main active ingredient in turmeric is curcumin which gives the spice its color. This recipe provides an easy method to get the most out of turmeric as it includes the addition of a little black pepper. Black pepper improves the absorption of curcumin.
- Ice cream
Sour ice cream sounds like a strange flavor but it really goes well with sweet fruits like cherries, blueberries or strawberries. The contrast between the sweet fruit and the sour yogurt provides a full flavor experience. Sweet and sour are different flavors which are detected in the mouth differently but also simultaneously.
- Baked cheesecake
Cheesecake is a typical high calorie dessert made from cream cheese, sugar and eggs, flavored with fruit or chocolate. When making baked cheesecake, sour cream is used which has a high fat content and adds the signature tangy flavor which helps to cut the sweetness and fat content of the cake.
By replacing the sour cream with sour yogurt cream cheese the flavor of the cheesecake takes on another level of interest. Sour yogurt has a higher amount of acid than sour cream as it has a longer incubation time giving the culture longer to acidify the milk. This has two effects; it consumes more of the sugar which increases the lactic acid.
- Hard yogurt cheese
This is a more creamier cheese which goes great on crackers, in sandwiches and added to salads. It is made by pressing additional whey out of yogurt cream cheese. It can then be aged by adding salt to the outer edge and drying it out to prevent it from molding. Aged sour yogurt cheese continues to acidify as the culture consumes more of the lactose in the cheese.