Marinades: acid, enzymes, yoghurt

Why

Most marinade ingredients penetrate only a few millimetres into the meat, even after many hours; both flavour and tenderising therefore work mainly on the surface, which is why marinating pays off most with thin slices and small pieces. Acid (lemon, vinegar, wine) and protein-splitting enzymes, for example from fresh pineapple or papaya, loosen proteins and connective tissue on the surface, but if they work too long the surface doesn't get tender – it turns mushy. Yoghurt and buttermilk are only mildly acidic and tend to be gentler on meat, while sugar and honey in a marinade help browning but burn easily on a grill or in a pan. Acid doesn't reliably kill bacteria, so marinate in the fridge, and a marinade that has been in contact with raw meat may only be used as a sauce after boiling.

How to do it

• Always marinate in the fridge, in a covered glass or stainless-steel container, or in a sealable bag.
• Leave fish and delicate meat in an acidic marinade for just 15–30 minutes, tougher cuts for a few hours, 24 hours at most.
• Let a marinade with fresh pineapple, papaya or kiwi work only briefly, never overnight.
• Set aside some marinade for a sauce before you put the raw meat in.
• Throw used marinade away, or bring it to the boil before serving.
• Pat the meat dry before cooking and wipe off a sweet marinade so it browns rather than burns.

If it goes wrong

A mushy surface after too long in an acidic or enzyme marinade can't be firmed up again; trim off the softest layer, or cut the meat into strips and stir-fry it briefly. Scrape off burnt sweet marinade and finish the meat over a gentler heat; next time add a sweet glaze only at the end.