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When you first start making yogurt at home you will want to know how to make yogurt which is similar the yogurt you can buy at the grocer. The thick tangy yogurt which makes for great toppings for fruit or can be made into dips and spreads.
Yogurt can be thickened by using a higher fat milk, heating your milk longer, fermenting it at a higher temperature, removing some whey or by adding thickeners or additional ingredients to increase the viscosity of the milk. Some of these methods can even be combined for extra thick yogurt.
If you read the ingredients on the back of a yogurt container you will find that the typical yogurt has a list of ingredients which are not from the cow. Instead the list could include:
- Guar gum
- Locust bean gum
Each of these ingredients is meant to improve the texture and thickness of the yogurt throughout its shelf life. Store bought yogurt has to go through a lot of handling with varying temperatures, storage times and transportation methods. This makes them susceptible to becoming disturbed causing it to be less thick.
Yogurt naturally thickens by the acidification of milk caused by the lactic acid bacteria found in the yogurt culture. The proteins found in the milk will come together and form a mesh like structure which loosely holds their shape when disturbed. The ultimate thickening potential of the yogurt depends on the amount of protein found in the milk, the thickness of the milk before frementaiton and the addition of thickeners which thicken the liquid found in the milk.
Increase fat content
For a creamier thicker yogurt try increasing the percentage of fat in the milk you use to make your yogurt. Skim milk makes a runny yogurt with low viscosity whereas whole milk will produce a yogurt which is thicker. Try this recipe for making heavy cream yogurt and see how much thicker your yogurt can be.
For very creamy viscous yogurt use half and half or whipping cream. This makes for a yogurt which is great for desserts, dips and gravies without the need for thickeners. The added milk fat makes yogurt which has a smooth texture making it good for making frozen yogurt as the water content in the yogurt is lower which helps to prevent crystallization in the yogurt as it freezes.
Benefits of using a higher fat milk
- No extra processing needed
- Produces a rich tasting yogurt without gluten
Drawbacks of using higher fat milk
- Yogurt will have a higher caloric content
- Tends to separate faster when heated
Why a higher fat milk makes thicker yogurt
Less water in the milk
The amount of water in the milk is effected by the fat content. The fat in the milk displaces the water in the milk. As the fat content goes up the water content goes down making for a thicker creamy yogurt.
Fat keeps the protein evenly dispersed
Yogurt thickens when the protein in the milk forms a mesh like structure which holds together in loose bonds. The fat in the milk helps to keep these bonds loose by keeping the protein pliable.
Fat is more viscose than water
Fat is just thicker than water, it flows slower which gives it a thicker consistency. The viscosity of a liquid depends on the size of the molecule in the liquid and since the fat molecule is much larger than that of the water it moves slower causing the yogurt to be thicker.
Use a different species of milk
Cow milk has a very steady amount of protein in it which allows it to thicken only so much but other species of milk have a different ratio of protein to fat and water. There are two species which are used regularly to make yogurt:
Sheep milk has the highest amount of protein over goat and cow milk giving it the most potential to thicken. The fat content is also higher than that of goat or cow with the added benefit of being naturally homogenized sheep milk resists the tendency to separate into whey and milk solids. This gives the yogurt a creamy texture.
Finally the amount of water in the milk is the lowest as the protein and fat content is higher. With less water the yogurt is more viscous and holds together better. This helps it to be thicker even after it has been stirred.
Benefits of using sheep milk for making yogurt
- No additives needed
- Milk does not need special processing
- Produces smooth and creamy yogurt
Drawbacks of using sheep milk for making yogurt
- Sheep milk is hard to find
- High caloric content
- Flavor different from cow milk yogurt
Goat milk yogurt can be used for stronger flavored dips, drinks and sauces. The goat flavor is prevalent and has a strong after taste which some do not like so it may not be acceptable for some recipes.
Goat milk is higher in protein than cow milk. This gives it more potential to thicken than cow milk. It is naturally homogenized making it resistant to separating into whey and milk solids. The fat content is also higher than that of cow milk increasing its viscosity and making the yogurt naturally thicker.
Benefits of using goat milk to make yogurt
- No additives needed
- Milk does not need special processing
- Produces smooth and creamy yogurt
Drawbacks of using goat milk for making yogurt
- Higher caloric content
- Only one fat content available
- Flavor different from cow milk yogurt
- Strong after taste
Why using a differnt species of milk can make thicker yogurt
Naturally homoginized milk has smaller protein molcules in it which are evenly dispursed throughout the milk. This along with the lower amount of water in either sheep or goat milk provides a better environment for the lactic acid bacteria to evenly acidify the milk. With smaller protein particles the yogurt tends to form a better protein structure which holds the yogurt together better.
Heat milk longer
Although heating the milk when making yogurt is important for a number of reasons there two effects on the milk which helps to make your yogurt thicker. Heating your milk to at least 180 F. is imperative to ensuring a successful yogurt incubation. To learn more aobut why it is important to heat your milk prior to incubating it for yogurt read this article.
Breaks down the proteins into smaller particles
There are several types of protein found in cow milk and all of them have varying size and shape. When you heat the milk up some of the larger proteins break down into smaller particles and get more evenly dispersed throughout the milk. This effect causes the structure of the thickened proteins in the milk to be spread out more helping to keep the smooth texture associated with yogurt.
Removes some of the water
Water is the least viscous liquid in milk. When you heat the milk up some of that water evaporates causing the remaining milk to be thicker. This is similar to why sheep and goat milk make thicker yogurt.
Benefits of heating the milk to make thicker yogurt
- No added ingredients
- Extra heating further pasteurizes the milk
Drawbacks of heating the milk to make thicker yogurt
- More time needed to make yogurt
- Higher chance of scorching the milk
- Loss of low temperature enzymes
Use a different yogurt starter
The store bought direct set packets which are often used to make yogurt have specific bacterial species in them which makes yogurt which is much like the store bought version but there are other types of yogurt starter from all around the world. These starters can be direct set types or heirloom types and will ferment milk in a wide variety of flavors and thicknesses.
Types of yogurt starters
- Heirloom yogurt starter
- Bulgarian style yogurt
- Greek yogurt starter
- Icelandic Skyr (which is actually a type of cheese)
- Finnish Viili yogurt starter
Each of these types are made with different species in the culture. The bacterial strains affect the proteins in the milk differently, breaking down some more than others and providing an environment conducive for the whey, fat and protein to remain combined causing the yogurt to become thicker.
Since each starter will make a different tasting yogurt you may have to try a few to find one you like with the consistency you desire.
Benefits of using a different starter culture
- Easy to use
- Can be direct set or heirloom culture types
- Adds variety of flavor to your yogurt choices
Drawbacks of using a different starter culture
- May have to try several types before you find one you like
- Direct set types require purchasing the starter regularly
- Heirloom types require constant care
Remove some of the whey
The whey is the liquid which forms on the top of a container of yogurt after it has fermented. This liquid is mostly water, bacterial culture and protein (the stuff protein powders are made from). By removing the whey from the yogurt you concentrate the solid protein and fat and end up with a thicker yogurt.
Some types of yogurt are made this way traditionally and commercially. The Greek yogurt at most grocers are usually normal yogurt cultures with some of the whey removed but other types have also traditionally been made this way.
How to remove the whey
Buy a Greek style yogurt making kit
These are fairly cheap and can be found in most kitchen stores, large department stores or online (Here is an Amazon link for your conveinence). Basically they have a basket on the top with a fine mesh on the bottom. The basket fits into a container which catches the whey as it drains out.
All you do is load the basket with yogurt and let the whey drain into the container below.
Use a coffee filter over a jar
This works for small amounts of yogurt.
- Fill a coffee filter with yogurt and place it over a jar
- Put the jar in the fridge and let it drain for 12-24 hours
- Scrape the thickened yogurt into a container and put it back into the fridge.
Hang it in a piece of tightly woven cotton cloth
Use this method when you have a lot of yogurt to thicken.
- Spread the cloth over a large bowl with the edges overhanging the bowl
- Pour the yogurt into the middle of the cloth
- Gather the edges of the cloth together and tie them together with a piece of string
- Hang the yogurt over the bowl for 8-24 hours
- If you are going to hang the yogurt for longer than 8 hours store it in a cool location
Let the yogurt separate naturally and pour off the whey
As the yogurt ages it continues to acidify. When this happens the protein and fat condense more and forces the whey out of the solids. This whey will form on the top of the jar which can be carefully poured off.
When you make yogurt if you let it ferment for longer than normal the lactic acid bacteria will continue to acidify the milk. This makes the protein in the milk to form closer and stronger bonds forcing the whey to collect on the top or bottom of the jar.
Once you have a large enough collection of whey pour some off the top or spoon the yogurt off the top and refrigerate it. As it cools it will thicken evenly.
Benefits of removing some whey to make thicker yogurt
- You can use any type of yogurt starter
- You can decide how thick you want your yogurt
Drawbacks of removing some whey to make thicker yogurt
- Takes time for the whey to drain out
- Have to do something with the whey
- Total amount of yogurt is less
Increase Fermentation Temperature
The theory for this is the various species which grow well in a warm environment tended to make thicker yogurt than those which did not grow as fast. Another idea is the protein and whey have a shorter time to separate during the fermentation because the acidification happens quickly at warm temperatures.
Traditional yogurt cultures will make thicker yogurt at a higher temperature. A range of 30-45˚C has been tested and it was found that yogurt on the upper range 40-45 ˚C was the thickest. At 40˚C the yogurt displayed good texture and thickness but tended to get ropey (the yogurt held together in strands) closer to 45˚C.
Whatever the reason if you have a warm location to ferment your yogurt or you have a temperature controlled yogurt maker try making your next batch at a warmer temperature to see if you like it.
Benefits of fermenting at a warmer temperature
- No added ingredients
- No special preparations needed
- Yogurt ready in a shorter timeframe
Drawbacks of fermenting at a warmer temperature
- Need a temperature controlled yogurt maker
- Yogurt will have a different taste
- Yogurt texture may not be to your liking
Use powdered milk
To make powdered milk the milk is sprayed into a heated chamber in a fine mist. The heat evaporates the liquid in the milk and a powder is left to settle in the container. Powdered milk has a high level of protein and depending on the source can contain some fat as well.
By adding some powdered milk to your fresh milk while making yogurt you can effectively increase the amount of protein in the milk. As the powdered milk rehydrates it also absorbs some of the water in the milk making for thicker milk.
It is the protein in the milk which forms the gel causing milk to thicken. An increased ratio of protein to other components in the milk will make for a thicker yogurt. Powdered milk is a good source of protein which will not substantially alter the flavor of the yogurt.
Powdered milk has a different flavor than fresh milk so do not add too much or the flavor will be effected negatively.
Benefits of adding powdered milk to thicken yogurt
- Remains a dairy product
- Easy to do
Drawbacks of adding powdered milk to thicken yogurt
- Can change the flavor
- Cannot be used in non-dairy yogurt
- Increased cost
Using gelatin to thicken yogurt
Gelatin is made by reducing collagen found in animal products into smaller protein particles. Once the collagen has been broken down it is tasteless and can be used to gel in a wide variety of foods including yogurt.
To use gelatin to thicken yogurt add the powder to the milk when it is cold and stir it constantly while it heats up. To ensure the gelatin is properly dissolved you have to heat the milk to at least 50 C. or 122 F. for at least 5 minutes. Once you have reached temperature make the yogurt normally.
As the milk cools the gelatin will form a gel in the liquid of the yogurt, the lactic acid bacteria will also help to break down some of the collagen and integrate it into the milk protein. Once the pH of the yogurt gets below 4.0 the protein solidifies and thickens the milk.
Although gelatin is tasteless it dies have a texture which can be a grainy, rubbery texture if too much is added. It can form a layer on the top or bottom of the liquid. Be careful to not overdo the amount of gelatin.
Benefits of using gelatin to thicken yogurt
- Easy to add while heating milk
- Cheap and easy to store
- Can add more or less depending on desired thickness
Drawbacks of using gelatin to thicken yogurt
- No longer a pure dairy product
- Changes the texture of the yogurt
- Once heated it becomes liquid again
Use starch to thicken yogurt
Starch has been used as a thickener for a wide variety of foods including gravies, sauces and pie fillings but is can also be used to thicken yogurt. There are several types of starch which can be used including:
Each of these provide different textures, flavors and need to be used in varying amounts.
The starch forms long strings of starch which get entangled together causing the liquid in the milk to gel. Since the lactic acid bacteria cannot breakdown the carbohydrate in the starch they remain in the yogurt and continue to provide thickening power throughout the life of the yogurt.
This is the usual way yogurt from the grocer is thickened as it provides long term thickening power and is fairly cheap to use.
Benefits of using a starch to thicken yogurt
- Can adjust the amount for the desired thickness
- Cheap to use
- Uses common ingredients
Drawbacks of using starch to thicken yogurt
- May not be gluten free
- Adds carbohydrates to a protein (can be harder to digest)
- Must be heated longer to form starchy strands
Use agar to thicken yogurt
Agar is made from a red algae and comes in powdered, granules or sheet forms. It can be used to thicken any water based liquids which includes milk. It forms a gel with the water found in the liquid and can also contain water in pockets making the solution semi-solid.
It does not need heating to activate but can stand heating without affecting its ability to thicken. It is relatively flavorless and adds little color.
To use it simply dissolve some into the milk before heating it.
Benefits of using agar to thicken yogurt
- Is vegetarian and vegan
- Is not affected by low pH
- Will keep for a long time
Drawbacks of using Agar to thicken yogurt
- Should not be used with heirloom yogurt cultures
- Can be more expensive and hard to find
- Is a highly processes food
Use xanthan gum to thicken yogurt
Xanthan gum is a carbohydrate created by a specific bacteria through fermentation. It is made industrially for use in commercial products like salad dressing, sauces and dips, in shampoo and conditioners and also in pest control products. To thicken yogurt with Xanthan gum add it to the milk before heating and treat the milk normally.
Benefits of using xanthan gum to thicken yogurt
- Does not need extra processing
- Can withstand low pH values without breaking down
- Maintains its thickening properties throughout a heat range
Drawbacks of using xanthan gum to thicken yogurt
- Is a highly processed industrial product (uses lots of energy)
- Can cause digestive upset in some people
- Cannot be used regularly with heirloom types of yogurt culture