Hi there. I have a 6.5 litre slow cooker, and usually use it for lamb and beef stews. The problem I have is when attempting to thicken my stews. As the slow cooker I have is on auto, I find that when I add cornstarch as my thickening agent, it doesn't thicken at all. I have tried transferring some of the liquid to a sauce pan and heating it up on high, but it makes the sauce too thick. Do you have any suggestions? Many thanks, Eve Attwell
Slow cookers can be useful for cooking stews, but generally the combination of low heat and a tightly fitting lid will mean that the auce doesn't get a chace to thicken (by reduction) and consequently the sauce can be a little thin. It is easiest to thicken the sauce once the stew has cooked as both flour and cornstarch (cornflour) require the cooking liquid to boil if it is to thicken.
Transfer the sauce to a saucepan and bring it to a simmer. There are 2 ways to thicken the sauce. The easiest is to use cornstach (cornflour) and to allow about 1 tablespoon per 250ml/1 cup liquid. Mix the cornstarch with an equal amount of cold water to make a paste (called "slaking" or "making a slurry"). Whisk this paste into the hot liquid and let it simmer, stirring, for 2 to 3 minutes. The sauce should thicken as it cooks and it is easy to add extra cornfliur if the sauce should be thicker.
You can also thicken the sauce using a beurre manie which is a paste made from equal quantities of softened unsalted butter and plain (all-purpose) flour. For each 250ml/1 cup liquid mix together 15g/1 tablespoon butter and 15g/1 tablespoon flour to make a thick paste. Whisk this paste in to the hot sauce 1 teaspoon at a time. Make sure you keep whisking when you add the beurre manie and let the sauce simmer for a minute, to see if it is thick enough, before adding the next teaspoonful. Keep adding the beurre manie by teaspoonfuls until the sauce is the thickness you require (you may need to make more beurre manie). Let the sauce simmer for an extra couple of minutes at the end, to get rid of any raw flour taste.