Tzatziki

Method

1. grate5 min
   coarse holes, skin on
   cucumber, into a bowl or straight into a tea towel. Leaving the skin on keeps some structure and colour; a peeled cucumber grates almost to liquid
2. season20 min
   in a sieve or towel, over a bowl
   the grated cucumber with half the salt and leave it. A cucumber is around ninety-six percent water held in cells, and salt draws it out through the cell walls by osmosis — skip this and the water comes out later, in the bowl, thinning the yogurt to a drink over about an hour
3. mash2 min
   flat of a knife with a pinch of salt
   garlic to a smooth paste rather than mincing it. Crushing ruptures more cells than chopping, which releases more allicin — the point here is even distribution, so that no single spoonful is aggressive
4. fold3 min
   squeezed cucumber, wrung hard
   squeezed cucumber + yogurt + garlic paste + dill + olive oil + lemon juice + remaining salt (+ mint, + vinegar, + pepper), turned together until uniform. Squeeze the towel until no more drips — expect to remove several tablespoons of water, and be firmer about it than feels reasonable
5. rest10 min
   covered, refrigerated
   so the garlic and dill spread through the yogurt. Longer than a few hours works against it: raw garlic in dairy sharpens as it stands, and by the next day a mild tzatziki has become a hot one