This is an excerpt from Libre del Coch
(Spain, 1520 - Robin Carroll-Mann, trans.)
The original source can be found at Mark S. Harris' Florilegium
94. Barley-water for Invalids. You will take barley and cook it the night before, according to the quantity that you wish to make. Then take a pullet or cockerel, and break its bones and then make a pot boil with water that is clean; and moderately, in such a manner that when you cast in the pullet or cockerel, the water only covers it; and [this is] if it is little, of necessity you will have to cast in more water if the pullet is larger, and it is necessary that it cooks longer; and it must cook or boil constantly, and never cease to boil. And do not cast in salt until the last, when you know that there is no more than a dishful of broth, because it will be more flavorful. And having done this, after the patient has supped, you will take a few peeled almonds and grind them with a little of the white meat of the pullet in a mortar; and blend them with the broth of the cockerel or pullet; and when you have strained it, put this milk in a little pot; and if you wish, cast in a tiny bit of starch; you can cast it in at the same time as the milk; and then take the barley or ordio when it is cooked, and take a hemp-tow which should not be very thin, and put it in that ordio or barley, and press down the hemp-tow very well, in such a manner that all the liquor comes out of the barley; then take that milk that you removed, and strain it through a sieve, in such a manner that little of the starch passes through it; and then strain everything again, the barley and all; and it should be a little clear and thin. Because in resting overnight it will turn thick. And I wish to say this now: let it cook the night before with sugar; and in the morning, when the patient is going to drink it, make it boil a little, and that will make it of great benefit; and when you give this barley-water, cast a little sugar over the dish; and if you don't wish to cast in starch, do not cast it in, [and see] that nothing goes into it.