how to thicken sauces?

[directhex]

any tips? whenever i try & make a sauce t ends up being all runny...

[Theo]

Mix a tablespoon or two of cornflour with cold water, then add it to your sauce... Mix it in, and it'll go slightly cloudy, but alot thicker.

Alternatively, you could just reduce it for longer (leave it to simmer for more time, etc).

[Nick]

As Theo said, you can use cornflour… here are a few ways to thicken up a sauce

Make a roux based sauce : This is essentially equal quantities of flour and butter, mixed together in a saucepan and cooked over a low heat until it goes ‘grainy’ in appearance. Let this cool a little and then add a little of whatever liquid you wish to thicken. Stir this in well and then keep adding the liquid until you get a smooth sauce. Place that back on the heat and stir continuously until it boils, then simmer for five minutes to cook out the flour taste. This is the way to make a white sauce like béchamel.

Use cornflour : This should be mixed with a little of the cooled liquid needing thickening, or water if you want. Make sure your liquid is boiling, then whisk the cornflour in, whisking as you pour. This stops it going lumpy. Add a little at a time, let it thicken as it takes a few seconds, then check the consistency. You can always add more if it needs it. Again, cook the sauce on a simmer for five minutes afterwards as this will cook out the flavour of the cornflour.

Use arrowroot : Use this the same way as cornflour. The advantage is that arrowroot will leave a sauce clear after thickening, the disadvantage is it’s expensive.

Use tomato puree : This is only really any good for tomato based sauces. Add the tomato as near the beginning as possible, e.g. after frying off your mince for a bolognaise. Cook it out for a few minutes and then add your stock etc. The sauce will thicken up as the puree cooks out.

Use butter or marg : This is a not very healthy way of thickening and gives a very rich sauce. It’s only really suitable for acidic sauces as the acid is needed to keep the fat in suspension. Its no good for large quantities of sauce either as you need roughly 2 parts butter to one part sauce. What you do is to cool the sauce to blood temp and then whisk in knobs of butter over a very gentle heat. To hot and the butter will split, too cool and it won’t melt. This sauce cannot be held and must used immediately.

Use potato: Usually reserved for soups, add diced potato in at the start of cooking and then puree in a blender. Also good for keeping dressings mixed as the starch in the potato will bind to the fat whilst staying in suspension in the liquid. Just blend in one or two over cooked new potatoes into a dressing and it’ll thicken up and stay emulsified.

Do a reduction : This only works if you have some form of thickening agent in the sauce already but the proportion of liquid is to great. Use caution as any starch based thickeners ( all of the above except butter) will burn to the bottom of the pan if you use too much heat. Good for cream based sauces though. The best cream to use for doing a reduction sauce is whipping cream. Unlike single cream, it won’t split if added to acidic sauces and unlike double cream, if you do over reduce it, it will easily be rectified by adding a little more liquid.

Hope this lot helps!