I am a musician, and the 18th-century composer Johann Sebastian Bach is known for having spent time at Café Zimmermann in Leipzig, and for his "coffee cantata" in which a woman declares her love for coffee (in cheeky comparison with her beau).
But how did they make coffee before electricity-powered machines? Was it just ground roasted beans soaked in fire-heated water? Or were there machines that produced pressure like modern espresso machines but with manual pumps? I know that air pressure for Bach's organs was produced using big bellows, could it have been a mechanism like that?
Here's an answer I wrote yesterday about the brewing process in 17th-18th century France. I don't have access to German-language literature, so I do not know how applicable this is to Leipzig circa 1730. However, coffee technology was still developing slowly in the early 18th century, so I doubt that it was that much different in Germany. Here are two texts from France and England, respectively from 1705 and 1722. The first is from Pierre Masson, a Parisian limonadier (seller of hard liquors and coffee) and the second is from Humphrey Broadbent, a coffee merchant in London. What is valuable here is that both men were coffee professionals, not just coffee lovers.
Masson, 1705
Take a pound of coffee beans, peel them well and put them in a well-scoured frying pan, or in a jam pan, or in a silver bowl or platter, or in an iron can turned on a spit: then roast them well over the fire, and stir them often so that they are evenly toasted, until they are black and iron-coloured, and take care that they are not burnt or reduced to charcoal. When this is done you shall pound them in a mortar and sift them, and if you have a mill you shall grind them. When you have ground it, and want to use it, you will boil a pint of water in a coffee pot, which you will remove from the fire once it is boiling and put in two spoonfuls of coffee, that is to say, half a quarter for a pint, and an ounce for a pint, which you will mix well with the water, then put the coffee pot back on the fire and boil it and when it wants to rise prevent this by taking it off the fire a little, and make it boil gently ten or twelve times. When it has boiled, put a glass of water in it to make the grounds fall to the bottom: once this is done, let it rest, draw it clear and serve it with china and powdered sugar, to be added as you like. When you want to keep the coffee for two hours, it must be boiled for half a quarter of an hour, otherwise it will spoil.
Broadbent, 1722
Particular Care ought to be taken in Roasting the Berries, for without doubt in that, Depends much the goodness of them Berries, Monsr. Bernier says, that at Grand Cairo, where there was above a Thousand Coffee-Houses, there was but Two Persons who rightly Understood that Art. I hold it best to Roast them in an Iron Vessel full of little Holes, made to turn on a Spit over a Charcoal Fire, keeping them continually Turning, and sometimes Shaking them that they do not Burn, and when they are taken out of the Vessel, spread 'em on fome Tin or Iron Plate 'till the Vehemency of the Heat is Vanished ; I would Recommend to every Family to Roast their own Coffee, for then they will be almost secure from having any Damaged Berries, or any Art to increase the Weight, which is very Injurious to the Drinkers of Coffee. Most Persons of Distinction in Holland Roast their own Berries. [...]
The common way of making this Liquor in our Coffee-Houses, is, to put an Ounce of Powder, to a Quart of Water, and to let it Boil till the Head is Boyled down, but this is a very silly way, for it is Manifest by Daily Experience, that if Coffee be but very little too much Boiled it is Spoiled, and grows either Flat, or Sour ; but if by long Custom you will not part from your Boiling, let it not Boil above a Minute, for the Boiling evaporates it's fine Spirit and Flavour, for which Reason I would advise the Infusion of Powder in Water, which will keep as good several Hours, as when first made. Put the Quantity of Powder you intend, into your Pot (which should be either of Stone, or Silver, being much better than Tin or Copper, which takes from it much of its Flavour and Goodness) then pour Boiling - Hot Water upon the aforesaid Powder, and let it stand to Infuse Five Minutes before the Fire. This is an Excellent Way, and far exceeds the common one of Boiling, but whether you Prepare it by Boiling, or this way, it will sometimes remain Thick and Troubled, after it is made, except you pour in a Spoonful or Two of cold Water, which immediately precipitates the more heavier parts at the Bottom, and makes it clear enough for Drinking.
As we can see, the brewing method in Paris and London coffee houses was roughly similar and quite simple: roast the beans, possibly in a device like this one, mill them, and then boil the ground powder in a pot while trying not to burn it. Broadbent recommends an alternative method where boiling water is poured on the coffee powder, but that may not have been applicable in a coffee-house. The marc was precipitated by adding cold water. Later French texts (Demachy, 1775) say that coffee houses sped up the sedimentation by adding fish glue (instead of cold water), though this was detrimental to taste and colour. The limonadiers tried to fix this by adding caramel, but "you [could not] fool the gourmets".
More sophisticated coffee-making devices, including some using filters, were developed in the second half of the 18th century, but true progress in coffee-making technology seems to have started in the last decades, and then there's a cornucopia of strange coffee devices appearing in the 19th century. At the time of Bach, however, coffee-houses were still relying on the old boiling method.
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