Deciding When to Thicken or to Reduce
Posted 10 May 2004 - 07:00 PM
Posted 11 May 2004 - 05:08 AM
First is to allow an opportunity to skim away any unwanted fat or grease, effectively cleaning up the liquid as it reduces. Best method for this is to add a small quanitity of cold water from time to time which will provoke a rush of foamy scum to the surface, This also compensates for some of the volume loss inevitable during reduction. The sauce or stock will darken the longer you keep this up and hopefully become more viscous also, giving body and substance to the liquid.
Secondly, reduction will concentrate the stock and this need only be done until the right intensity of flavour is reached. At this point you decide how thick the sauce should be and thicken it as needed. Three main methods here. For white stock based sauces arrowroot is fine. It acts like gelatine and used in small quantity will give the same sort of body that prolonged reduction might. Its disdavantages are twofold, the effect wears off after any further prolonged boiling also the texture will suffer if too much is used - so dilute the arrowroot in cold liquid and whisk it in little by little.
Butter will thicken sauces but at the cost of making them richer, the more you use the less vibrant the underlying flavours in the stock or wine. This is fine for some things but not for everything.
Best is plain flour. But this is easily the most tricky method for the bad name that flour based sauces acquired, for stodginess and heaviness, is regularly well deserved. The flour must be used in small quantities proportionate to the total liquid. maybe 2 tablespoonfuls per gallon and then either roasted or fried until light brown before use. Chefs will either dust the bones with the flour before roasting them or add a tablespoon to the frying aromatic vegetables that they are adding to the stock. This way the flour cooks out completely.
If this is too much song and dance for a pot of sauce then use potato flour - fecule de pommes de terre - which is the least intrusive of the cornflour - cornstarch - type thickeners. Add it the same way as arrowroot, diluted in cold wine or water the whisked in a little at a time
Posted 11 May 2004 - 07:07 PM
I enjoy a little "song and dance" but I hadn't thought of the potato flour bit. Thank you very much for your succinct treatise on thickening and reducing. I have another question on a different subject which I will broach as a new topic.