Does milk kefir have alcohol?

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There are two types of kefir which need to be considered, store bought kefir which does not contain alcohol and homemade kefir from kefir grains which on average contains 2.5% alcohol.

Store bought kefir is alcohol free but homemade kefir can have between 0.5-3.0% ABV.  The alcohol is produced by the yeast cultures found in the kefir grains and varies depending on the milk’s lactose content, fermentation time, oxygen availability and fermentation temperature.

The amount of available fermentable sugars

It is well known that the amount of alcohol that yeasts produce is dependent on the amount of fermentable sugar present.  The use of a hydrometer which measures the specific gravity of a solution is used in wine and beer making to determine how much sugar is dissolved in the solution before the yeasts begin to ferment it. 

Milk is not like a fruit juice or wart which is used to make wine or beer but it still contains a fair amount of sugars which the yeast use to produce alcohol.

The amount of oxygen

In general yeasts require oxygen to grow which has led people to believe that if they ferment their kefir in an anaerobic environment their kefir will have less alcoholic content but that is not exactly true.

Alcohol is not something which the yeasts need or want in the solution rather it is a byproduct of respiration.  This means that the yeasts excrete alcohol into the solution as waste.  This waste is produced in higher amounts when the yeasts are stressed, like surviving in an anaerobic environment.  One yeast which exists in kefir grains is Saccharomyces cerevisiae produces a high amount of alcohol when placed in an anaerobic environment.

The ambient temperature

The ambient temperature of the fermentation affects the cultures in the kefir grains differently.  Saccharomyces cerevisiae, which has been used in the wine industry fermention process, produces alcohol over a wide range of temperatures.

Generally the yeasts are less active at lower temperatures allowing the bacterial cultures to use the sugars to produce lactic and acidic acid.  This makes the kefir more tangy and acidic tasting and will take longer to ferment. 

If the kefir is fermented in the higher range the yeasts especially Saccharomyces cerevisiae produce large amounts of alcohol quickly. 

The activity of acetobacter

Acetobacter can be a problem in the wine industry as it converts the alcohol in the wine into acetic acid changing the wine into vinegar.  Not something which they want in the wine industry but when it comes to kefir we appreciate the action of the acetobacter in the kefir.  It lowers the amount of alcohol simply by using it as food.  The more acetobacter in the kefir fermentation the more alcohol will be converted into acetic acid.  The problem with this is the change in pH with the added acidic acid makes the kefir sour.

How to lower the alcohol content in kefir

To lower the alcohol content of your kefir and still get a kefir you like may take some experimentation.  The above factors all play a part in the final taste and texture of the kefir so changing one will affect the others. 

The amount of sugar in the milk

Each type of milk whether it be cow’s milk in some form, goat, sheep or any other available milk has a different chemical makeup which includes how much available sugar it contains. 

Cow’s milk varies depending on the amount of milk fat in it.  Homogenized milk has the least amount of available sugars as some of the energy is tied up in the milk fat.  This makes it less available to the yeasts.  Once you get down to 0% or skim milk the sugars are mostly available to the yeasts to produce alcohol.

Goat’s milk is naturally homogenized and has less sugars then cow’s milk and sheep’s milk is between the two.

Choosing the type of milk affects the final flavor and texture of your kefir so you will have to experiment with what you like.  Skim milk makes a thin fizzy kefir which is great for just drinking.  As the fat content increases the kefir gets thicker and less fizzy. 

Kefir made with 10% table cream or whipping cream makes a high fat creamy kefir which resembles yogurt in texture but has a buttery flavor with little alcohol or fizziness.

Ferment with Oxygen

Fermenting your kefir in an aerobic environment helps to lower the alcohol content in three ways.

1. It helps the yeasts respiration to be efficient and as a result they will produce less alcohol overall
2. Some of the alcohol will evaporate due to the air exchange and its volatile nature
3. Acetobacter can grow and convert some of the alcohol to vinegar

Acetobacter is the bacteria which consumes alcohol and produces acetic acid which is the main acid in vinegar.  The reason the activity of acetobacter is important to the alcohol content is that it uses the alcohol in its respiration.  Acetobacter is most active within the temperature range of 25 to 30 degrees Celsius

Ferment your kefir at a temperature between 20 to 25 degrees Celsius.  This range helps to keep the various organisms healthy and growing.  Both the Acetobacter and the lactic acid bacteria grow rapidly at a temperature range of 20-30 degrees Celsius. 

The yeasts tend to grow rapidly in warmer temperatures which can overwhelm the other cultures like acetobacter and the lactic acid bacteria.  When this happens the kefir will be more alcoholic as more of the available sugars have been used by the yeasts. 

At lower temperatures the dominate cultures will change and as a result the flavor and mouth feel will also change.  At lower temperatures there will be less yeast activity and as a result less carbon-dioxide which makes it less fizzy. 

Can you get drunk off kefir?

To be considered drunk in a legal sense your blood alcohol percentage needs to be 0.08 or above for you to be considered drunk.  How much alcohol you must consume to have that much alcohol in your blood stream is dependent on factors like your weight, metabolism, gender and drinking pattern but on average this is a good number to use.

It can take only one drink of regular alcoholic beverage to reach a blood alcohol percentage of 0.08.  One 12 ounce bottle of beer at a 5% alcohol content consumed in an hour can do it so it is possible that if your kefir alcohol content was 2.5% and you drank 24 ounces of it in under an hour your blood alcohol may get close to 0.08%.  Essentially you will have to consume a large sized container of kefir in under an hour if only alcohol percentage and time were considered. 

Another consideration is the time it takes for the kefir to move from the stomach to the small intestine.  The stomach absorbs some of the alcohol in any alcoholic beverage at a rate much lower than that of the small intestine.  That rate depends on the concentration of the beverage.  For highly concentrated beverages such as hard liquor the rate is much higher than that of beer and would be even less with a concentration of kefir at 2.5%. 

This is important because milk takes about 90 minutes to pass from the stomach to the small intestine.  While the kefir is still in the stomach the alcohol is being absorbed into the blood and metabolized by the liver at a much slower pace than from the small intestine.  This allows the liver to deal with the alcohol and keep the blood alcohol level lower.

Once the kefir reaches the small intestine it has an even lower alcohol concentration making its absorption slower.

The bottom line is that yes you could get drunk on kefir if you were to consume high amounts of it quickly and consistently over a few hours but it is unlikely that you could consume enough kefir to reach that point.