Rescues · TO PEEL
The dish tastes bitter after adding citrus zest.
Why it happens
White pith came with it. Pith is uniformly bitter and none of it should be there.
Recovering it
Over-peeled is a loss of yield rather than a ruined dish. Over-blanched tomatoes are still fine for a cooked sauce, just not for anything raw. Bitter zest cannot be rescued once it is in — the compounds are not volatile and will not cook out — so taste before committing it. Discoloured potatoes are cosmetic only and disappear entirely once cooked.
The mechanism
Skin is not automatically waste. It carries fibre, colour, and in citrus almost all of the aroma; it also holds a vegetable's shape during cooking and browns well. The decision to remove it is about what the layer does in this dish. Potato skin is tough in a purée and excellent roasted. Tomato skin separates into leathery curls in a long-cooked sauce and is unnoticeable raw. Aubergine skin turns bitter and rubbery in some varieties and not others. Citrus pith is uniformly bitter and always comes off. The mechanism behind blanching to peel is thermal: a few seconds in boiling water expands the flesh just under the skin and breaks the bond between the two layers, and the cold shock afterwards stops the flesh cooking further.
The full TO PEEL lesson — how to tell, where to practise it, what it carries to.