Sumik in the old milk diet
In Chapter III of The Miracle of Milk, Macfadden describes setting milk aside in a warm place for 24–36 hours until it clabbered, then beating it smooth with an egg whisk. He suggested it for people who could not take sweet milk, and for those whose stomachs lacked acid. He was following the fashion started by the scientist Élie Metchnikoff, who linked the long lives of Bulgarian peasants to their soured milk.
Clabber, buttermilk, kefir and dahi: the differences
| Drink | How it is made | Texture |
|---|---|---|
| Clabbered milk | Milk left to sour with whatever bacteria it already contains | Thick, set, slightly lumpy |
| Traditional buttermilk | Liquid left after churning butter from soured cream | Thin, tangy |
| Cultured buttermilk | Low-fat milk fermented with added lactic cultures | Pourable, tangy |
| Kefir | Milk fermented with kefir grains (bacteria and yeasts) | Thin, fizzy, sour |
| Dahi / yoghurt | Milk fermented with a yoghurt starter | Set and creamy |
Why not just leave milk out?
Pasteurised milk left on the side usually spoils rather than clabbers, because pasteurisation removes the friendly bacteria that would sour it. Raw milk will clabber, but you have no control over which bacteria grow, and harmful ones can grow too. Using a known starter fixes both problems.
A safe modern “sumik” recipe
- Warm 1 litre of pasteurised whole milk to about 40°C (warm to the touch, not hot).
- Stir in 3 tablespoons of live plain yoghurt or 100 ml of cultured buttermilk.
- Cover and keep warm for 8–12 hours, for example in an oven with only the light on, or wrapped in a towel.
- Check it. It should be thick, smell pleasantly sour and taste tangy. If it smells unpleasant, is pink, or has fuzzy mould, throw it away.
- Chill, then whisk smooth before drinking, just as Macfadden suggested.
- Keep in the fridge and use within 5 days. Save a few spoonfuls to start the next batch.
Is soured milk good for you?
Fermented milks provide the same protein and calcium as milk, and many people with mild lactose intolerance find them easier to digest because some of the lactose has been used up by the bacteria. Live yoghurts and kefir may support gut health, although research is still developing. They are a good everyday food. They are not, despite the old claims, a cure for disease.
Related reading
- The milk diet explained
- Raw vs pasteurised milk
- Chapter V: Macfadden on lactic-acid milks after the diet
This article is general information, not medical advice. Please speak to your doctor or a registered dietitian before making big changes to your diet.