In mid 1990s Manfred Junius book was withdrawn from sale in Italy precisely because of his being too explicit about the first part of volatilization of tartar.
Then things changed, and Alchimia Verde, la preparazione alchemica delle sostanze vegetali, ed. Mediterranee, came back on the market. The chapter I translated and commented has been taken from 1982 edition, thus before the editorial closing off. And I actually don’t know whether the book newly put on market has been re-edited and changed or kept the same lines of 1979 – 1982 editions. I also don’t know about german and english editions.
My translation from Alchimia Verde, la preparazione alchemica delle sostanze vegetali, final part of chapter 3 ‘Three Philosophical Principles and the Elements‘:
“Old masters did not know that calcined tartar was almost carbonic potassium. The latter can be obtained, for example, with the sublimation of degreased wool ashes, as also with the incineration of plant and the extraction of salts from the calcined ash. The chemical formula will be the same. But the old alchemists knew how to make volatile Tartarus Calcinatus and how to distill it to cure with it certain diseases. For example, they used it to dissolve the salts of uric acid in the human organism.
The celebrated volatilization of Tartar is used to clarify once again the difference between the points of view of chemistry and alchemy. Let us go deeper into the volatilization of tartar.
Tartar is the salt of tartaric acid. The latter is found in fruit as well as in the marcs in the free state, in the form of salts of calcium and potassium. The tartaric acid is also known as dioxy succinic acid.
Having two asymmetric carbon atoms, there are known three different structural forms of tartaric acid:
After having thoroughly analyzed these forms, we note they can be dextrorotatory, right-handed, when components divert the plane of polarized light of a positive angle, as we can see below:
and levorotatory, left-handed, those that turn it with a negative angle, as below:
An equimolar mixture of R and S forms are optically inactive, because their action is canceled, as below:
The forms of tartaric acid have an identical number of atoms, but the situation of the two central -OH groups is different.
In nature, at the free state, there is found only the dextrorotatory tartaric acid which can form two different potassium salts, by replacing one or two of potassium atoms. In the first case we have the replacement of a hydrogen atom with a potassium. This is potassium bitartrate or potassium hydrogen tartrate, which is dextrorotatory:
In the second case below we have the replacement of two hydrogen atoms with those of potassium. This formula identifies potassium tartar, which is neutral and also dextrorotatory:
Only the first of these two salts is found in abundance on the walls of the barrels in which the grape fermentation took place. In alchemy this raw salt is called Tartarus Crudus (1). This raw tartar, together with potassium hydrogen tartrate, also contains calcium tartrate.
A treatment with charcoal, clay and heat (classic alchemists propose tiles powder) can ‘purify’ the tartar, which thus becomes Tartarus Depuratus, also called cream of tartar Cremor Tartari, with not more calcium tartrate inside, in fact, it is composed of about 99% of potassium hydrogen tartrate. The latter is no soluble in alcohol, but in water heated at 100 C. (for example, one may dissolve 1 part of tartrate in 20 parts of water).
If Tartarus Depuratus is calcined, it forms a black mass such as coal, which is not more potassium acid tartrate, but is alkaline.
For alchemists the result obtained by the calcination of Tartarus Depuratus is simply Tartarus Depuratus Calcinatus, even if chemists, rightly in terms of their knowledge, insist that this substance is derived from tartar, but it has nothing to do with it.
Let’s make another step forward. The substance is further transformed with the processes of volatilization. There are several ways to get to the volatile state of tartar, including the coobation (2) process with wine vinegar, which is the most known and quoted among alchemists. (See, eg, Knorr von Rosenroth Artzney-Aufgang der Kunst; and Ortus Medicinae by J. B. van Helmont).
From a chemical point of view, the original tartar is thus constantly transformed by several treatment processes. Only the material used at the beginning of the steps to ‘give wings to our subject’ deserves the name ’tartar’; according to chemistry it is not volatile, while for the rest it comes to other substances.