Soured milk denotes a range of food products produced by the
acidification of
milk
Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modulati ...
. Acidification, which gives the milk a tart taste, is achieved either through bacterial
fermentation or through the addition of an acid, such as lemon juice or
vinegar
Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to ...
. The acid causes milk to coagulate and thicken, inhibiting the growth of harmful bacteria and improving the product's shelf life.
Soured milk that is produced by bacterial fermentation is more specifically called
fermented milk or
cultured milk.
Traditionally, soured milk was simply fresh milk that was left to ferment and sour by keeping it in a warm place for a day, often near a stove. Modern commercial soured milk may differ from milk that has become sour naturally.
Soured milk that is produced by the addition of an acid, with or without the addition of microbial organisms, is more specifically called acidified milk.
In the United States, acids used to manufacture acidified milk include
acetic acid
Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main componen ...
(commonly found in vinegar),
adipic acid,
citric acid
Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in t ...
(commonly found in lemon juice),
fumaric acid,
glucono-delta-lactone,
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid. It is a component of the gastric acid in the dig ...
,
lactic acid
Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natur ...
,
malic acid,
phosphoric acid
Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solutio ...
,
succinic acid, and
tartaric acid
Tartaric acid is a white, crystalline organic acid that occurs naturally in many fruits, most notably in grapes, but also in bananas, tamarinds, and citrus. Its salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a c ...
.
Soured milk is commonly made at home or is sold and consumed in Europe, especially in Eastern Europe (Bulgaria, Belarus, Poland, Russia, Ukraine, Lithuania), all over the countries of the former Yugoslavia (Macedonia, Serbia, Montenegro, Bosnia and Herzegovina, Croatia, Slovenia), Romania, Hungary, Greece, Finland, Germany, Scandinavia and Slovakia.
It is also made at home or sold in supermarkets and consumed in the Great Lakes region of Somalia and
Eastern Africa (
Kenya
)
, national_anthem = " Ee Mungu Nguvu Yetu"()
, image_map =
, map_caption =
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, capital = Nairobi
, coordinates =
, largest_city = Nairobi
, ...
,
Uganda
}), is a landlocked country in East Africa. The country is bordered to the east by Kenya, to the north by South Sudan, to the west by the Democratic Republic of the Congo, to the south-west by Rwanda, and to the south by Tanzania. The south ...
,
Rwanda,
Burundi
Burundi (, ), officially the Republic of Burundi ( rn, Repuburika y’Uburundi ; Swahili: ''Jamuhuri ya Burundi''; French: ''République du Burundi'' ), is a landlocked country in the Great Rift Valley at the junction between the African Gr ...
and
Tanzania
Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands ...
). It is also a
traditional food of the
Bantu people
The Bantu peoples, or Bantu, are an ethnolinguistic grouping of approximately 400 distinct ethnic groups who speak Bantu languages. They are native to 24 countries spread over a vast area from Central Africa to Southeast Africa and into Southern A ...
of
Southern Africa
Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number ...
.
Since the 1970s, some producers have used chemical acidification in place of biological agents.
[
]
In recipes
Raw milk that has not gone sour is sometimes referred to as "sweet milk", because it contains the sugar
lactose
Lactose is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix ...
. Fermentation converts the lactose to
lactic acid
Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natur ...
, which has a sour flavor. Before the invention of
refrigeration
The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, ht ...
, raw milk commonly became sour before it could be consumed, and various recipes incorporate such leftover milk as an ingredient. Sour milk produced by fermentation differs in flavor from that produced by acidification, because the acids commonly added in commercial manufacture have different flavors from lactic acid, and also because fermentation can introduce new flavors.
Buttermilk
Buttermilk is a fermented dairy drink. Traditionally, it was the liquid left behind after churning butter out of cultured cream. As most modern butter in western countries is not made with cultured cream but uncultured sweet cream, most mod ...
is a common modern substitute for naturally soured milk.
See also
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References
{{Authority control
Fermented dairy products
Russian drinks
Russian dairy products