lemon
Also known as: lemon slices
A sour citrus fruit used three ways: juiced for acidity and brightness, zested for its aromatic oil, and sliced as a garnish. Zest and juice come from the same fruit but serve different purposes, so when both are wanted, zest before juicing -- there's no zesting a fruit once it's been squeezed flat.
Buying guidance
Choose lemons that feel heavy for their size with smooth, taut skin -- a light, thick-skinned lemon has less juice inside than a heavy, thin-skinned one of similar size, even though they can look alike. Rolling a lemon firmly on the counter under your palm before cutting it helps release more juice.
Substitutions
- Lime -- similar acidity with a more floral, less rounded aroma; works well in most savory or drink uses.
- Bottled lemon juice, for the juice only -- convenient but flatter in flavor than fresh, and provides no zest.
- White or cider vinegar, for acidity only in a savory dish -- sharper and lacks any citrus aroma, so use less and expect a different flavor.
Tips & common mistakes
When zesting, grate only the thin, colored outer layer -- the white pith just beneath it is bitter, and it's easy to go too deep with a fine grater without realizing it until the flavor turns harsh.
Storage
Whole lemons keep noticeably longer refrigerated than left out in a bowl -- expect a few weeks refrigerated versus under a week at room temperature. A cut half stays juicier longer stored cut-side down on a small plate or in a container than wrapped cut-side up.