
Fresh lemon is a yellow citrus fruit whose juice and oil-rich peel are a core souring and aromatic element in the bar.
Bottled juice is flat and often sweetened and has no place in a sour. Lime is equally acidic and differently aromatic. For zest alone, any citrus peel works and changes the perfume.
Meyer lemon
A citron-and-mandarin hybrid rather than a true lemon: sweeter, less acidic, more floral. It cannot carry a sour on its own — the drink comes out flabby — but it cuts a clean twist.
Bottled lemon juice
Preserved and aroma-free, and sometimes sweetened; it is an ingredient for cooking and a compromise in a drink.
Lemons hold for weeks and are commercially stored at 10–13 °C, which is warmer than a domestic fridge — the drying from the ends is chilling injury as much as age. Unwaxed fruit is worth finding if you use the peel. Fruit is warmed above 10 °C before commercial juice extraction, which is the reason bars bring out a shift’s worth ahead of service.