I do some historical cooking out of old cookbooks, like Amelia Simmons' American Cookery or The Art Of Cookery Made Plain and Easy. One thing I've noticed is that these cookbooks use way more egg yolks than whites. For example, I prepared an 18th century feast one night and ended up with 10 leftover egg whites in a jar.
This left me wondering, what did they do with the egg whites? Given the extreme frugality of cooks centuries ago, which included using every scrap of stale bread and every bit of a pig including the oink, I find it impossible to believe that they were wasted. They must have used them for something … but that's not in the recipes I have. So, questions:
- Are the cookbooks we have simply not representative of actual cookery of the 15th-18th century? That is, are they purely posh cookery and as a result did actually waste the egg whites?
- Or were the egg whites used for some other purpose that required a lot of whites, maybe even a non-culinary purpose?
Help me solve this mystery. Thanks!
Best Answer
Another high-volume specialist use for egg white was mortar. Specifically, it was used very frequently in the Middle Ages, in the standard lime and sand mortar: a 2017 study suggests that 6% egg albumen (I assume by weight) provides the strongest mortar.
It was not the only binding agent available to construction, but at least in the Middle East and in Europe, it was one of the most easily procured. Its role is to aerate the mortar, which is essential in preventing thermal contraction damage (ice or heat), and modify its hydration (usually by allowing a lower water-to-cement ratio, increasing strength and water resistance while still being workable).
The use of egg white in construction persisted into the late 19th century in the colonial Philippines. According to one report, this use of egg white in the buildings transformed native Filipino desserts.