Clabbered milk is unpasteurized milk that has been allowed to sour. Once milk has been pasteurized, many of the good bacteria have been killed. While pasteurization does make milk stay fresh longer and makes it safer to drink, soured pasteurized milk mainly contains bad bacteria. When unpasteurized milk sours, the good bacteria, or probiotics, are the ones that usually multiply. This curdled, clabbered milk may then be eaten like yogurt or cream cheese. To make clabbered milk, cooks need to keep a volume of unpasteurized milk in a warm place until it thickens.
Those who live near farms or organic food markets generally have the best chance of finding unpasteurized whole milk. Others may have to search a bit for this kind of dairy product. Some organic food companies use refrigerated transportation to ship this kind of milk to customers within a certain distance. The milk should typically be kept refrigerated until the cook is ready for the clabbering process to begin.
A glass mason jar typically works best for making clabbered milk. Cooks should sterilize these jars by boiling them in distilled water and drying them with clean towels. The jars should ideally have tightly-fitting lids. The cook may then pour the milk into a jar and cap it tightly. Setting the jar in a warm place, such as above the refrigerator or in a warm cabinet, should help the probiotic bacteria begin to grow. This process takes a bit of time, so patience is key.
The cook should typically shake the jar of milk for several minutes every 24 to 48 hours. This helps distribute the bacteria through the milk, allowing it to clabber more evenly. It also allows the cook to check the consistency of the milk. Clabbered milk is typically thick and white, something like thick cream. When the milk takes on this appearance, the cook may place it in the refrigerator and use it in cooking.
Cooks who simply cannot find unpasteurized milk anywhere may try making clabbered milk from pasteurized products. The milk must be gently warmed over low heat. When bubbles begin to form around the edges of the pan, the cook may add a spoonful of probiotic yogurt. This adds good bacteria back into the milk and allows it to ferment safely. The resulting mixture may then be poured into a mason jar and allowed to thicken for several days, just as in the process above.