Homemade Soup Day

What the day is

Homemade Soup Day is observed on February 4, positioned in the part of winter when it is the obvious thing to cook.

Origin and background

Soup is probably among the oldest prepared foods, constrained historically by the need for a vessel that could sit over heat. Archaeological evidence for cooking in pots goes back many thousands of years, and boiling extracts nutrition from bones, tough cuts and fibrous vegetables that cannot otherwise be used, which is why it appears wherever food is scarce.

The thing that separates good homemade soup from the tinned version is browning. Sweating or frying the onions, and searing any meat, before liquid goes in produces the Maillard reaction, a set of transformations between amino acids and sugars that creates hundreds of new aroma compounds. This cannot happen once liquid is added, because a wet pan cannot exceed the boiling point of water and the reaction needs considerably more heat than that. Everything poured into the pot at once produces a thin, flat soup no amount of simmering will rescue.

The second lever is salt timing. Salt added early draws water out of vegetables and seasons them from within; salt added at the end sits on the surface and tastes sharper for the same quantity.

Acid at the finish is the most underused trick in home cooking. A squeeze of lemon or a splash of vinegar stirred in off the heat lifts a soup that tastes dull and heavy, and most people reach for more salt when acid is what is missing.

Stock is worth making from scraps kept in the freezer, and bones roasted first for the same browning reason.

How to take part

• Brown the aromatics properly before any liquid goes in. This is the whole difference.
• Salt early and adjust late.
• Finish with acid before reaching for more salt.
• Keep a freezer bag of vegetable trimmings and bones for stock.
• Make double and freeze half flat, which thaws in minutes.