Buttermilk

• 1. Introduction

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  Buttermilk is a fermented dairy drink with a name that points straight at butter. Yet most of the buttermilk sold in industrialized countries today never came near a churn. That small mismatch hides a larger story about bacteria, refrigeration and changing habits. This documentary asks what the drink was before cold storage, how a factory now imitates it, and why a pale, tangy liquid is still poured in some regions while fading in others. It also asks what it does inside a mixing bowl, and what a cook can do when a recipe calls for it and the carton is empty.

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• 2. Left Over From The Churn

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  Before refrigeration and homogenization, fresh raw milk was simply left to stand so the cream could drift to the top. While it waited, lactic acid-producing bacteria already present in the milk began to ferment it. That souring did a useful job. Fat from cream with a lower pH clumps together more readily than fat from fresh cream, so the butter came more easily. What remained after churning was nearly fat-free milk, with traditional buttermilk holding less than 0.5 percent fat.

  The acid carried a second benefit. An acidic environment discourages potentially harmful microorganisms, which stretched the drink's shelf life. The method still had a weak spot, because it was prone to spoilage during fermenting and churning, especially when hygiene was poor or the milk was not kept cool.

  Refrigeration, together with dairies that handled fresh milk in near-aseptically clean conditions, largely removed those problems. It also changed butter itself. In industrialized countries, butter is now typically made from uncultured cream, called sweet cream, so the churn no longer leaves behind the soured liquid that gave buttermilk its start.

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• 3. Still Poured Today

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  During Ramadan, buttermilk appears on tables in Arab culture, where it is commonly sold ice cold alongside other dairy products. It is often drunk for iftar, the meal that breaks the fast, and for suhur, the meal before dawn. In the Indian subcontinent, a glass may be served with roasted maize.

  Traditional buttermilk remains common in many households across South Asia, the Middle East and various parts of Europe. In other Western countries it is seldom found.

  Warm climates give the drink a practical edge. Unrefrigerated milk sours quickly in the heat, but fermentation prevents further spoilage, so a soured drink keeps better than fresh milk would. Drinking buttermilk therefore remains common in warmer regions, where the fermentation itself acts as the safeguard.

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• 4. Culture In A Carton

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  Commercial cultured buttermilk is made the same way as yogurt. The starting point is fresh milk that has been pasteurized and homogenized. Makers then inoculate it with a culture such as Lactococcus lactis, Lactobacillus bulgaricus or Streptococcus lactis. These produce the lactic acid that sours and thickens the milk. A further bacterium, Leuconostoc citrovorum, is added to boost the buttery quality. The aim is to simulate the bacteria that occur naturally in the traditional product.

  The chemistry starts with lactose, the main sugar in milk. As bacteria ferment it into lactic acid, the pH of the milk falls. Casein, the primary milk protein, then precipitates. The milk curdles, a change also called clabbering, and ends up thicker than plain milk.

  Both versions contain lactic acid, but they differ in body. Traditional buttermilk is thinner than the cultured kind sold in cartons.

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• 5. The American Rise And Slide

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  Cultured buttermilk reached American shops commercially in the 1920s, and its first drinkers were mostly immigrants. Sales then grew for decades, peaking in 1960 at 517 million kilograms a year. After that, drinking declined. By 2012, annual sales had dropped to less than half the 1960 peak.

  The food industry kept using it anyway, in condensed and dried forms. Liquid buttermilk goes mainly into the commercial making of baked goods and cheese. Buttermilk solids are used in making ice cream and are added to pancake mixes to produce buttermilk pancakes.

  Powdered buttermilk also reaches home kitchens. Home cooks use it to help baked goods rise higher and to add tang to dips, marinades and rubs without thinning them. It can also be sprinkled over fruits and vegetables as a topping.

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• 6. Chemistry In The Kitchen

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  Soda bread depends on a quiet reaction. The acid in fermented buttermilk meets sodium bicarbonate, the leavening agent, and the two produce carbon dioxide. That gas is what lifts the dough.

  Cooks also turn to buttermilk for marination, especially for chicken and pork.

  When no buttermilk is on hand, a substitute called acidified or acidulated buttermilk fills in. The recipe calls for 15 ml of a food-grade acid, such as distilled white vinegar or lemon juice, stirred into 200 to 250 ml of milk. After about 10 minutes the milk curdles and is ready to use. Any fat level works, though whole milk is usually chosen for baking.

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• 7. Nutrition By The Glass

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  A 100 ml measure of whole buttermilk delivers 62 calories of food energy. Modern commercial buttermilk made from whole milk is 88% water, 3% protein, 3% fat and 5% carbohydrates. It is a moderate source of vitamin B12, at 19% of the daily value, and of riboflavin, at 13%.

  Low-fat buttermilk is lighter, at 43 calories per 100 ml. Skimmed milk comes in at 35 calories, and whole milk at 61, just one calorie under whole buttermilk.

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