Exact difference between demi glace and bordelaise?

Question

This feels like a stupid question, but I've spend a fair bit of time reading about this without finding an answer... I'm trying to understand the French mother sauces and their derived sauces. I am confused about the differences between demi glace and bordelaise, their place in the 'system', and whether roux is used in either.

Reading about espagnole here, I learn that espagnole

• Starts with a brown roux, and
• Can be used to make demi glace AND bordelaise.

This confuses me, because I've encountered recipes for either, which have not mentioned roux. For example, this demi glace recipe by ChefSteps makes no mention of flour or roux - only reduced wine and stock.

Similarly, this bordelaise recipe, for instance, is virtually identical (except for adding butter towards the end).

Hence, I'd be grateful if anyone could help me understand

1. Precisely what is the difference between demi glace and bordelaise?
2. Is roux used in either? If not, how can they be derived from sauce espagnole?

Answer 1

For references, see the sauce chapter of Ma Cuisine (no on-line copy available to my knowledge) and the fond and sauce chapters of A GUIDE TO MODERN COOKERY, both by Auguste Escoffier.

In summary (one should read the references for the full story):

Espagnole sauce is made from brown roux, brown stack, bacon fat, a small amount of butter and is simmered (I skip the herbs, spices, and diced vegetables).

Demi-glace is made from espagnole "to which at the last minute is added some rather strong brown veal stock or fine meat jelly". Meat jelly (glace de viande, meat glaze) is brown (and/or white) stock reduced until it coats a spoon and becomes syrupy.

Bordelaise is made of reduced wine, demi-glace, a little tomato sauce, and beef marrow (again I skip herbs, etc.).

So, in answer to question 2: roux is used for espagnole, but no additional is used for demi-glace or bordelaise.

Part of the confusion appears to be naming; e.g., brown sauce can refer to both brown stock and espagnole or meat jelly vs. meat glace vs. meat glaze.

The ChefSteps recipe seems to be meat glaze (glace, jelly) rather than demi-glace (or half glaze). I couldn't access the YouTube video.

Answer 2

Demi glace is usually used as a base to make other sauces, it can also be used by itself.

Demi glace is used to make Bordelaise sauce.

Roux is not used in either cases.