Walnuts: Brain-Shaped Nuts, Tannins and the Best Ways to Use Them

Walnuts are among the oldest tree foods eaten by people, and they have been cultivated for thousands of years in Persia and Central Asia. English walnut, also called Persian walnut, is the common supermarket kind. Black walnut, native to North America, has a much stronger, wilder flavour and a very hard shell. China, the United States and Iran are leading producers of the common type.

Flavour and the bitter note

Walnuts are rich, slightly sweet and a bit bitter, because their papery skins contain tannins. Fresh walnuts taste buttery and gentle, while stale ones taste sharp. A quick soak or a short blanching can reduce the bitterness a little, but most people like the contrast. Lighter coloured halves are generally milder.

Walnuts and omega-3

Walnuts stand out among nuts because they contain a good amount of alpha-linolenic acid, the plant omega-3 fat. The body only converts part of this to the long-chain omega-3s found in oily fish, but it is still a valuable part of the diet. Their high content of polyunsaturated fat also explains why they go rancid quickly.

Cooking ideas

Toasted walnuts go in banana bread, brownies, carrot cake and coffee cake. In savoury cooking, they appear in Georgian sauces such as satsivi and bazhe, in Italian walnut sauce for pasta, and in French salads with blue cheese and chicory. Middle Eastern muhammara blends walnuts with roasted red peppers and pomegranate molasses. Crushed walnuts make a good vegetarian base for burgers, meatless taco filling and pâté. Pair them with apples, pears, figs, beetroot, honey, maple and dark chocolate.

Toasting and bitterness

Toast walnut halves at 160°C (320°F) for 7 to 10 minutes. Cool them, rub off any loose skins if you wish, and chop. Toasting mellows tannins and boosts aroma. Do not leave them unattended, because they burn quickly and burnt walnuts taste acrid.

Walnuts provide polyunsaturated fats, protein, fibre, copper, manganese and magnesium, along with plant polyphenols. A portion is a small handful, around 30 grams.

Storage

Rancidity is the main enemy. Whole walnuts in the shell keep for months in a cool, dry place. Shelled walnuts should be stored in an airtight container in the fridge or freezer. Taste one before using them in a recipe: if it is bitter, sour or smells like paint, discard the lot, because rancid walnuts ruin baked goods.

Cautions

Walnuts are a major tree nut allergen, and reactions can be serious. People allergic to walnuts may also react to pecans, and care is needed with shared factory lines. Black walnuts may also carry a risk for people allergic to other tree nuts. Walnuts can be hard for some people to digest in large amounts. Discard any that look mouldy.

This article is general information, not medical advice.