Commercial buttermilk is a common dairy product found in most grocery stores and used frequently in baking, cooking, and drink recipes. But what exactly is in the carton of buttermilk you buy at the store? This article will explore how commercial buttermilk is made and what ingredients it contains.
What is Buttermilk?
Traditionally, buttermilk was the liquid leftover from churning butter. The agitation of the cream would leave behind a tangy, acidic liquid that cooks found useful in recipes. The term buttermilk comes from the fact that butter solids were removed, leaving just the milk.
Modern commercial buttermilk, however, is different from the traditional version. Commercial buttermilk sold today is made from skim or low fat milk and fermented with a culture to produce the characteristic tang. The milk may be fortified with powdered skim milk to achieve the desired thickness. Salt, stabilizers, and emulsifiers may also be added.
So in essence, commercial buttermilk is just cultured low fat or skim milk. The culturing process gives it a thicker consistency and sour taste that sets it apart from regular milk.
Buttermilk Cultures
The key component in commercial buttermilk production is the buttermilk culture. This is a mixture of lactic acid bacteria added to pasteurized skim or low fat milk.
Common bacteria used in buttermilk cultures include:
- Lactococcus lactis: Converts lactose to lactic acid, producing acidity
- Leuconostoc citrovorum: Creates diacetyl, which gives buttermilk its distinctive flavor
- Lactococcus cremoris: Contributes to taste and aroma
When added to milk, these bacteria ferment natural milk sugars (lactose) into lactic acid. The increase in acidity causes proteins in the milk to thicken and develop a tart flavor. The bacteria also generate aromatic compounds like diacetyl, acetoin, and acetaldehyde which give buttermilk its signature tang.
After culturing, the buttermilk is cooled, sometimes homogenized to disperse the solids evenly, and packaged for distribution and sale. Stabilizers or emulsifiers may be added to improve texture and shelf life.
Nutrition of Buttermilk
Since commercial buttermilk starts with skim or low fat milk, its nutrition profile is similar. Buttermilk is an excellent source of:
- Protein
- Riboflavin
- Calcium
- Phosphorus
- Potassium
A 1 cup serving provides:
| Nutrient | Amount |
|---|---|
| Calories | 98 |
| Fat | 2.2 g |
| Carbohydrates | 12 g |
| Protein | 8 g |
| Calcium | 28% DV |
| Vitamin B12 | 18% DV |
The culturing process actually makes the vitamin and mineral content more bioavailable and easier to absorb. The bacteria generate lactic acid which helps break down proteins, making the calcium, phosphorus, and B vitamins more accessible.
Buttermilk has a thicker consistency compared to skim milk due to coagulation of milk proteins. However, it contains slightly less carbohydrates and calories since some of the sugars are converted to acid during fermentation. The tangy taste comes from increased acidity and production of aromatic compounds.
Types of Commercial Buttermilk
There are a few varieties of buttermilk found in most grocery stores:
Cultured Buttermilk
This is the most common type of buttermilk. Regular, cultured buttermilk starts with pasteurized non-fat or low-fat milk and goes through a culture process as described above. Stabilizers are usually added to improve texture. This type of buttermilk is readily available at most markets.
Powdered Buttermilk
Powdered buttermilk is simply cultured buttermilk that has been dried into a powder. To make it, liquid buttermilk is spray dried or freeze dried into a concentrated powder. The powder is rehydrated with water before use. Powdered buttermilk is more shelf-stable for baking needs.
Concentrated Buttermilk
Concentrated buttermilk has had some of the water content removed to make it thicker. Usually the milk is cultured first, then evaporated to reduce water content by 25-50%. This makes it easier to transport and store. It is diluted with water before use in recipes.
Whey Buttermilk
Whey buttermilk starts with whey, the liquid byproduct of cheese making. The whey is cultured to produce the acidic tang of buttermilk. It is thicker and creamier than traditional buttermilk.
Goat or Sheep Buttermilk
Some brands produce cultured buttermilk from goat or sheep milk. These have a similar tang but distinct grassy, goaty, or sheep flavors compared to cow’s milk buttermilk. They can be used the same way in cooking.
How is Commercial Buttermilk Made?
Commercial buttermilk on store shelves goes through the following basic production process:
- Pasteurization: Milk is briefly heated to at least 145°F to destroy pathogens and spoilage organisms.
- Homogenization (optional): Milk fat globules are broken down into smaller sizes to disperse uniformly and prevent separation.
- Fortification: Powdered milk or concentrates may be added to achieve desired fat/solid content.
- Culturing: Buttermilk starter culture is added and allowed to ferment, acidifying the milk.
- Cooling: Fermented buttermilk is rapidly cooled to 4°C to stop culturing.
- Ripening: Buttermilk is held for 4-12 hours at cool temperatures to allow flavor to develop.
- Second cooling: Buttermilk is cooled again to stabilize prior to packaging.
- Fortification: Salt, emulsifiers, and stabilizers may be mixed in.
- Packaging: Buttermilk is homogenized one last time then packaged for distribution.
The primary steps are pasteurization, fortification, culturing/ripening, and cooling. This process results in the thick, tangy liquid buttermilk that you pour over pancakes or use in biscuits and muffins.
Buttermilk Substitutes
When cooking with buttermilk, you can make some substitutions in a pinch:
For 1 Cup Buttermilk:
- 1 cup plain yogurt + 1 tablespoon lemon juice
- 1 cup milk + 1 tablespoon vinegar or lemon juice
- 1/4 cup yogurt + 3/4 cup milk
- 1 cup sour cream thinned with milk
- 1 tablespoon vinegar or lemon juice + enough milk to make 1 cup
Any acidic liquid like vinegar, lemon juice, or cream of tartar can be used to curdle milk to mimic buttermilk. Allow it to sit for 5-10 minutes after adding the acid to fully thicken.
Powdered buttermilk substitute can be made by mixing 1 cup nonfat dry milk powder with 1 tablespoon lemon juice or vinegar and enough water to make 1 cup.
Commercial Buttermilk Takeaways
- Commercial buttermilk is made by culturing skim or lowfat milk to produce thickness and tangy flavor.
- Buttermilk cultures contain bacteria that ferment natural milk sugars into lactic acid.
- The increased acidity coagulates milk proteins to create the signature thickness.
- Buttermilk is nutritionally similar to skim milk but easier to digest due to bacterial pre-processing.
- Types include cultured, powdered, concentrated, whey, goat, and sheep buttermilk.
- To make commercial buttermilk, milk is pasteurized, fortified, cultured, ripened, and packaged.
- In a pinch, buttermilk can be substituted by curdling milk with an acidic ingredient like lemon juice or vinegar.
So in summary, the buttermilk you buy in the store is made by adding beneficial cultures to low fat milk to thicken it and produce a tangy flavor. The same basic process used centuries ago still produces the tasty, thick buttermilk we enjoy in recipes today. Understanding exactly what’s in buttermilk and how it’s made can help you select and substitute buttermilk for all your cooking needs.