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One of the areas in which modern esoteric alchemy actually does overlap with medieval alchemy is in the distillation of acetates. It appears to have been the case that for centuries that many processes used acetic acid rather than mineral acids; vinegar is used in the first alchemical text, the Physika et Mystika of pseudo-Democritus and in many recipes since then. With the invention of distillation various processes involving it continued in use, and our starting point here is a recipe which caught my eye 4 or 5 years ago when I started researching alchemy.

It is in the ‘Book of the quintessence’, by John of Rupescissa, (a 15th century translation of it published by the Early English Text Society) where it says:

Take the myn of antimony aforesaid, and make thereof al so sotil a powder as you can then take the best vinegar distilled, and let it sont upon a soft fire til it be coloured red, and so do many times, and when you have gathered all your vinegar coloured, put it then in a distillatorie, and first the vinegar will ascend, then after you shall see marvels, for you see as it were a thousand drops of blessid wiyn discende down in manner of reed drops, as it were blood, by the pipe of the lymbike, the which liquor gather together in a rotumbe”

This is a very distinctive description, and I formulated a hypothesis about it quite rapidly, although it has taken a long time to get round to the associated experiment. Because the red drops are so distinctive, I thought it would be easy enough to observe and replicate.

The problem was how to get a red liquid in the first place? Since vinegar is specified, it had to be mixed with something that gives a red solution in vinegar. Now it turned out that well known historian of science, Lawrence Principe, had a related problem with the works of Basil Valentine, a pseudonymous early 17th century alchemical author. His book ‘The triumphal chariot of alchemy’ included using vinegar to get a red extract from a glass of antimony, something which did not seem possible when it was tried by other people using what antimony was available to them. But Principe showed that the solution was to use iron rich antimony ore from Eastern Europe, as Valentine had specified Hungarian Antinomy, as opposed to other antimony ores which did not contain significant amounts of iron.
When I met him at a conference I asked if anything else gave a red vinegar solution, and he assured me that nothing else did. I haven’t found any other information that disagrees with that either. By the way, antimony in this context means antimony sulphide, the sulphur rich ore. Definitely not the metal itself, which was known of a century after Rupescissa, but probably not at his time. And if, as some have suggested, it actually means lead sulphide, you’ll still dissolve some of that, and any iron present in the lead ore, into the acetic acid solution that distilled vinegar actually is.
So, the first thing is getting a red iron rich solution, which I did by dissolving steel wool in acetic acid:
iron vinegar nearly there

Now, a difference between the ancient and modern alchemists (I suppose I might as well relent and call them alchemists, although their aim is entirely ‘spiritual’) is that the modern ones use an entire suite of metals, some of which were not known before the 16th or 17th century, from gold to zinc via lead and iron. This thread on a forum gives a comprehensive run down of methods and products:

In fact after reading the above thread, it seems that you can get red or yellow liquids from distilling other metallic acetates, including lead, which made me more confident about the possible outcome. Naturally I had to try it myself, and in doing so I can see what goes on and what affects the results, which is especially important since I am trying to do it in a more authentic way. There is also the point that some people who post on that sort of forum are untrustworthy, seeking power or influence and are willing to make things up in order to get it, so you should not trust their word completely.

Interestingly, one poster in the thread says that green acetate gives a green tint, and also one quotes an old book (the “London Encyclopaedia, or universal dictionary of science, art, literature, and practical mechanics” from 1839) to say that copper acetate gives green tinted acid. Which fits with the green lion of George Ripley, if, instead of using lead oxide, you use copper, and it might be so coloured because a little of it flies up the alembic and gets redissolved in the liquid that is condensing out during the distillation.
This point is somewhat important, we shall come back to it later.

My experiment:
Now, the first part of the distillation, the removal of the excess water and acetic acid, took a long time, in part because the liquid bumped a great deal – it superheated and turned into steam at the bottom of the cucurbit, making it ‘bump’ and causing the liquid inside to fly up the neck of the cucurbut. However I had chosen one with a long neck, and none of it actually appeared to escape into the alembic. It did mean I had to heat it really slowly and gently, with my thermocouple registering 200C, which was barely hot enough to keep the wood burning. Charcoal would perhaps have been a better option, also a slightly different furnace design would have helped. I deliberately placed the thermocouple right by the bottom of the cucurbit, so I could judge the heat reaching it directly from one side of the furnace, although since it was swathed in lute it would take some time to reach the same temperature inside as outside.
Anyway, I kept at it, and eventually no more liquid came over. As you can see the newer setup included a long downtube:
iron acetate distillation setup as used for acid making

This ensured that most of the vapour condensed before it reached the collection vessel, helped by the wool on the tube which was dampened regularly and could sometimes be seen steaming because of the amount of heat transferred to it. But it was already apparent that the cooling pipe was not really long enough to condense all the vapour coming over. The reciever was cooled in water at air temperature, which was around 9 or10 C, hardly warm, but you could feel the water warming up in a few minutes due to the amount of heat it was absorbing. There was a large volume of condensate from the nearly half a litre of acetic acid solution, that condensed on the alembic rapidly:
iron acetate distillation alembic condensate at start
And ran down the downspout, filling the large beaker I had cooling in a pot of water:
iron acetate distillation filled collection vessel

I kept the temperature low until I was sure that pretty much all liquid was gone and the bumping had stopped, then I ramped it up slowly, aiming for 500C. The first main burst of fumes came after 300C had been passed. They filled the alembic:
acetic acid distillation white fumes

And then the receiving vessel:
iron acetate distillation white fume product

The first products were a bit yellow, and the final product, from over 400C, is a yellow/red liquid:
iron acetate distillation product

Some might say it is red, in the right light. Does that mean it fits the original description? Maybe it does. But remember also it is possible to get some metal ions to come over, which in this case might colour it red. So maybe all red liquids are down to iron presence or else, sulphuric acid? Obviously this isnt sulphuric acid, but it is an interesting substance none the less. But of course if you get a red liquid from gold or some other metals, then clearly the product is not dependent on iron for its colour! Moreover, would this shade of colour be called red by a medieval person? Their ideas about colour and brightness were a little different from us, and they had fewer words for colours. So I think I have made a red liquid, or a variety of it.
But I also lost a fair bit of vapour that simply did not condense in the 50cm of tubing and collecting vessel, which would mean the product is not as red as it should be.

Therefore an immediate conclusion is that I need better cooling than the 50cm long downspout, perhaps a good serpent, used for distilling wine. It is a kind of long windy tube used to ensure the condensation of all the vapour coming out of the alembic. They are seen especially after the 16th century as more illustrations are made, although they were definitely around in the 1290’s; some credit their invention with permitting greater and easier production of spirits of wine. The way Rupescissa writes, you are probably expected to use similar equipment as that you used previously to distill alcohol seven times, so it seems likely that a serpent is implied and is already attached to the alembic. Once again, the assumptions made by the author are far from clear, the reasons for which are rooted in the place of practical work in society and the obsessive interests of whoever does the practical work. Also Rupescissa was not a practical technician, and a lot of his knowledge came second hand. If anything, he is the equivalent of a modern crank who has a fad diet based on something he experienced once. So his instructions are not always as practical and clear as other period instructions for the likes of ink.

Another method of cooling would be to work out a way of inserting the down tube through a container which has iced water in it; between that and the collector being cooled, it seems I should be able to collect all the vapour. But a bigger collector would help too. It was, but shouldn’t have been, a bit of a surprise how much volume was required to hold the vapour, and how slow it was in condensing, even although its boiling point was above that of water. The oily vapour behaved somewhat differently from water in the same situation.

The red liquid smells odd too. It certainly isn’t pure acetone or acetic acid, I know what they smell like and of course the colour is wrong, acetone being clear like water.

Now, the scientific explanation, bearing in mind I am not an organic chemist and don’t have full access to papers and textbooks on what is a rather old and irrrelevant area of chemistry.
Some old books suggest that the distillation of metallic acetates gives acetic acid, but if you carry on distilling, you get something else, which is called pyro-acetic spirit.

Modern works on the distillation of metal acetates include:
http://repository.ias.ac.in/12396/1/12396.pdf, which seems to think that acetone and acetic acid are the main products, which is clearly not the case here because these are clear liquids with distinctive smells that are different to what I produced here.

Modern esotericist Robert Allen Bartlett carried out distillations of metallic acetates, and suggests the use of an ice bath, but prefers such methods as calcium chloride and ice which can reach -40 to -50C, to ensure all vapours are condensed (see his book ‘The way of the Crucible’). This immediately suggests that the cooling the medieval alchemists used was a very long tube. He also analysed the various products. Because of the way he worked, and pre-existing ideas about what was the ‘sulphur’ he was after, he split it all into more fractions than I would have, but the interesting thing is that he claims to have found, amongst other chemicals, 3,5-dimethyl phenol, eugenol and isoeugenol, and other phenols. Getting phenols from acetic acid is a bit odd; but an organic chemistry book I have (‘Introduction to organic chemistry’ by Feiser and Feiser) on page 357 shows that acetone on treatment with concentrated sulphuric acid produces mesitylene and of course once you have aromatic rings, with oxygen or OH groups off them, many further exciting reactions can occur.

This is a good example of the oddness of alchemical work, because it happens in the gap between reactant and product, and the inefficiency is the cause, although the alchemists didn’t know that. A great deal of alchemy is like that. Because modern chemistry is based on a great deal of knowledge of what things are and how they work (It is not going too far to say that chemistry as a discipline is finished and has little more to find or achieve) you carry out reactions to achieve the best possible result. Whereas in alchemy, a lot of reactions go on in the vapour phase in the cucurbit and alembic, which then explains why the modern gravimetric analysis methods simply don’t find the same weird chemicals as you get from the dry distillation done the old fashioned way.

One of the other interesting things is that Bartlett quotes liberally from 17th century distillers and alchemical books, which clearly say to use lead oxide and vinegar, producing a set of crystals, then distilling that at a high temperature to get a red and oily liquid, showing that this product was well known about in the early modern period, but working out the place of it in society and alchemy deserves another post.

Now, if we agree that it is a red liquid, then it pushes the use of metal acetates to produce red liquids back to the 14th century, and from my point of view shows the efficacy of the heating, equipment and cooling methods, even if the texts aren’t very explicit on what they were.

On the other hand it is important to admit that the redness from such a simple work as is described by John of Rupescissa might be from some iron blown up into the alembic, and redissolved by acetic acid into red drops.
This however does not do away with the other descriptions of red oils, especially when they come from a gum, which would not bump or spit as much as a liquid when distilling. In fact it wouldn’t surprise me if the colour were due to both some iron in solution and the oil itself. More experimentation would be required, paying specific attention to the apparatus used and how it constrains the process of distillation and affects the product quality.

You’ll note that throughout this I have assumed that the alchemical texts are talking about specific practical work and real products. This is my particular angle of attack on alchemy, and does not necessarily do away with other interpretations. For instance I agree that many alchemists were not practical at all, that others lied or were confused, and, especially later, alchemy wassubsumed into a wider spiritual world view. Nevertheless, I think the fact that you can produce liquids and oils coloured the way the manuscripts say they should be from the substances they say they are, is more than just suggestive; I can never prove it exactly, but I think all this very likely shows what they did actually worked. After all, is not a recipe more persuasive and useful when it produces the substance it says it does?

And as for the uses of this quintessence of antimony of John of Rupescissa, it is to be used to take away the aches of wounds, presumably by placing on them, but it needs to be putrified “in a rotombe and seelid in fyme”, which instructions are rather unclear on the matter. The other problem is that he writes of how to use the quintessence, but tells of how to make many quintessences, from alcohol, antimony, gold, and human blood. The fact that the red drops he refers to may well have contained a great deal of phenol and similar compounds would perfectly explain the effect on wounds, as they would act as a form of antiseptic, and kill off pretty much anything in the wound. This includes some human cells as well, but that doesn’t seem too bad an exchange. Perhaps it can be used in other ways, but that is not clear to me at this moment.

There is plenty to think of from this one experiment, and it makes it clear that a number of other alchemical recipes involving acetic acid, such as that from George Ripley’s works, will produce red drops. One last interesting thing – why did Principe, who was following the works of Basil Valentine, not carry out this distillation? It’s in one of the works attributed to Valentine, which talks about the production of a red liquid from antimony. Doing it would be entirely appropriate, yet he hasn’t as far as I have read.