How to sweat onions and mushrooms, etc

The process of sweating food means exactly what you think it means – making them release water. Almost all cooking methods involve releasing water from food, but when you’re given the instruction to sweat something in a recipe, it generally means that you need to keep the released water from evaporating to a certain extent.

For example, when sweating onions or mushrooms, you need to put a lid over the pan in which you are frying them in order to trap the condensation. This means the water doesn’t evaporate, they don’t dry out, and they end up cooking in their own expelled water. As long as you have them on a low heat, they can go on stewing in their own juices for quite a while, intensifying their flavour.

A good guideline as to when onions or other ingredients have been sweated properly is when they’re soft and floppy but not swimming in their own juices. If a massive amount of water is released during the cooking and doesn’t look like it’s going anywhere, just take the lid off and let it evaporate, stirring often. It’s not ideal, and if your ingredient is letting out loads of water, you may want to investigate why it’s got such a high water content.

For example, when you fry cheap bacon, you get loads of watery rubbish released from the meat because it’s bulked out with saline solution. But good bacon releases hardly any water, because it’s mostly meat and fat. It’s worth looking out for.

How to reduce saltiness in soups/stews

It’s easy to accidentally over-salt soup, stocks and stews and for ages I thought that there wasn’t anything you can do about it. But it turns out it’s quite easy to repair something that’s too salty: just put a raw potato in the soup or stew. As the potato cooks it will absorb some of the salt and then before you serve up just remove the potato. Simple.

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How to blanche tomatoes

To blanche tomatoes, you immerse them in boiling (or just-boiled) water for a short period (only about 15 seconds) and then immediately pop them into some cold water to stop the tomatoes cooking any further. You can then peel off the skin much easier.

How much is a “knob” of butter?

A knob (heh) of butter usually means about a walnut-sized lump.

How do you “reduce” a liquid?

Reducing a liquid means just what it sounds like – making what there is smaller. You do this by simmering or boiling the liquid so that the water evaporates. This concentrates the liquid so it has more flavour. It’s not an exact science, so if a recipe says “reduce by half”, you simply simmer or boil it until you think there is half as much liquid as there was in the beginning.

When making stock, it can be useful to reduce the liquid right down if you’re not going to use it straight away because it saves room in your fridge or freezer. When you want to use the stock you can then add water to bring it up to its former concentration. For example, if you’ve made 500ml of nice stock and then reduced it by half so that it’s 250ml, when you want to use it you add 250ml of water to restore it to the right concentration.

What is meant by “Al Dente”?

Al dente means, literally, “To the teeth”. What it means in practice is that when you bite into it, it should still be slightly firm. For example, when cooking pasta, the pasta should still be slightly undercooked in the centre and should provide some resistance when you bite it. When pasta is overcooked it is soft all the way through and feels a bit soggy.