Nutritional breakdown per 100g
Protein3g
Fat1g
Saturated fat1g
Carbohydrate5g
  of which sugars5g
  starch0g
Fibre0g
Energy 
37kcal
157kJ
Na56mg
Ca120mg
Fe0mg
Vitamin A10µg
Vitamin C0mg
Vitamin D0µg
Vitamin E0mg
Vitamin B60.1mg
Vitamin B120.1µg

Buttermilk

A Sour milk product produced from either by products of cheese production or by the fermentation of low fat or skimmed milk

Buttermilk

Traditionally this is the by product of cheese production and is the whey left over after the curds have been separated for use in making cheese. Originally used as a drink in its own right it is now priarily used as a commercial ingredient. Most buttermilk available for domestic use is not whey but is produced from the fermentation of low fat or skimmed milk. Both forms produce a naturally sweet and sour milk product. The sweetness comes from the lactose in the milk while the sour flavour comes from the lactic acid produced in the fermentation of the whey or milk. Although this has a very high water and low fat content the presence of lactic acid also causes it to be naturally thickened.

In cooking it is commonly used in sour dough mixes, sour breads and scones. The lactic acid reacts with baking powders to create a raising agent. Suitable alternatives would be milk and sour cream mixes although changes may need to be made to adequately replace the raising agent effect.