The British probably have as many different recipes for making gravy as they have gravy boats from which to pour it over their roast beef. But, a spot of chemistry can improve not only the flavor, texture, and color, but give gravy a healthy boost. Here’s the definitive chemical guide to making gravy:

Ingredients

The juices from a roast joint of meat, preferably beef
Flour
Vegetable water (cabbage)
Iodized table salt
Teaspoon of dark soy sauce
Pepper
Gravy browning if you prefer a darker gravy

Method

Roast your meat joint on a bed of halved onions, carrots and celery
on to which juices from the meat will slowly trickle. When the meat is
cooked, remove it from the roasting tin along with the vegetables.
Sprinkle a small amount of plain flour over the meat juices and fat.

Stir to form a dough (roux) gradually adding the water in which
vegetables have been cooked, preferably cabbage water. Ensure all the
meat juices and brown deposits of paste on the bottom of the roasting dish
have dissolved.

Then add iodized salt to taste and a teaspoon of dark soy sauce (rather than gravy browning) or a little red wine. Simmer to reduce the volume of liquid to the right consistency, stirring occasionally.

The science bit

Protein from the collagen of the meat. Vitamins, particularly B1, B6, folic acid, riboflavin and nicotinic acid.

Carbohydrate from the flour and gravy browning. Gravy browning is
caramelized sugar and can be bought, or it can be made using the recipe
in Mrs Beeton’s Book of Household Management published in 1859 (when she was just 23 years old). This says to heat sugar until it caramelizes but does not become too dark.

Minerals such as sodium and iodine.

Monosodium glutamate (MSG) from the soy sauce which enhances umami, the taste sense of deliciousness.

In the rush to get the chemistry right for your Sunday Roast, don’t forget your Yorkshire puddings…they’re a whole different recipe.

Thanks to the Royal Society of Chemistry for the cookery lesson.