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Potato Cheese
Potato cheese are very highly esteemed in Germany; they can be made of various qualities, but care must be taken that they are not too rich, and have not too much heat, or they will burst. Boil the potatoes till they are soft, but the skin must not be broken. The potatoes must be large and of the best quality. When boiled carefully peel them, and beat them to a smooth paste in a mortar with a wooden pestle. To make the commonest cheese, put five pounds of potato paste into a cheese tub, with one pound of milk and rennet; add a sufficient quantity of salt, together with cara-ways and cumin seed, to impart a good flavour. Knead all these ingredients well together, cover up, and allow them to stand three or four days in winter, and two or three in summer. At the end of that time, knead them again, put the paste into wicker moulds, and leave the cheese to drain until they are quite dry. When dry and firm, lay them on a board, and leave them gradually to acquire hardness in a place of very moderate warmth; should the heat be too great, as we have already said, they will burst. When, in spite of all precautions, such accidents occur, the crevices of the burst cheeses are, in Germany, filled with curds and cream mixed, some being also put over the whole surface of the cheese, which is then dried again. As soon as the cheeses are thoroughly dry and hard, place them in barrels with green chickweed between each cheese; let them stand for about three weeks, when they will be fit for use.
This is a genuine German farmhouse cheese of the eighteenth and nineteenth centuries, but it is described in a way that cannot be reproduced safely in a modern kitchen. The points below explain what the instructions leave out and why those omissions matter.
- No measured acidity, and a low-acid baseCooked potato sits around pH 6, well above the pH 4.6 that keeps Clostridium botulinum in check, and the recipe supplies no starter culture to drive acid development. A dairy-and-starch paste held at room temperature for days with nothing but rennet and an unstated amount of salt is an uncontrolled ferment, not a cheesemaking process.
- "A sufficient quantity of salt"Apart from the drying, salt is the main preservative hurdle here, and the quantity is left entirely to the maker. In modern cheesemaking salt is weighed as a percentage of curd mass precisely because the margin between a safe cheese and a spoiled one sits in that figure.
- "Rennet" is not a quantity eitherRennet in this period was often a strip of salted calf stomach steeped in whey or brine, of unknown strength, though standardised extracts existed by the later nineteenth century. Either way there is no way to translate the word into a dose, and in any case rennet coagulates casein; it does nothing to make the potato portion safe.
- Days at ambient temperatureStanding three or four days in winter and two or three in summer is a description of weather, not of temperature control. Cooked potato held in that range is a classic substrate for Bacillus cereus, whose emetic toxin survives later drying and is not destroyed by heating.
- Milk of unknown provenance"One pound of milk" is a weight measure, something like three-quarters of an imperial pint, but the real difficulty is that it would almost certainly have been raw farm milk. Nothing in the process reaches a pasteurising temperature at any point, and the finished cheese is never cooked.
- Barrelled with chickweedPacking dried cheeses in a closed barrel interleaved with foraged green plant material introduces soil organisms and moisture into a low-acid product in a near-anaerobic space. Chickweed (Stellaria media) is edible, but the recipe uses it as packing material and says nothing about cleaning it.
- The bursting is a symptomThe text treats splitting as a heat problem to be patched with curds and cream. Cheeses that swell and split may instead be doing so because gas-forming bacteria are at work inside them, which is a signal to discard rather than to repair the surface.
- If you want to make itDishes under the name Kartoffelkäse survive in German and Austrian regional cookery, though these are generally potato spreads rather than rennet-set cheeses like this one. If you want to attempt a cheese, use a current recipe with weighed salt, a defined starter culture, pasteurised milk and stated ripening temperatures.
Kartoffelkäse belongs to the long stretch of German rural cookery in which the potato, established across Prussia and Saxony through the later eighteenth century, was pressed into service to extend expensive dairy. A cheese made mostly of potato paste with a pound of milk to five pounds of potato is an economy cheese in the plainest sense: the caraway and cumin do the flavouring work that a long, milk-fed ripening would otherwise do, and the same seeds season the related soft cheeses of the region. The entry reads as observation of what is done in Germany rather than as a set of workable directions, and it carries neither weights for salt nor any notion of temperature beyond winter and summer. The passage is best read as a record of how a farmhouse dairy managed its surplus, and of how much of that process lived in the maker's judgement rather than on the page.