The Fourth Part of the Prosperity of Germany

(NB. Whoever can obtain such pure salt as this, which possesses a hexagonal hexahedral shape, such as is prepared in my laboratory, will be able to use it as being by far purer.) The vessel itself, to which the butter, prepared and cleaned in the manner we have described, must be committed, ought to be prepared as follows. A new oak cask must be soaked not in ordinary but in strong salt water, so that it thoroughly imbibes the salt; in this, the butter, washed in the said manner, must be compressed and condensed so tightly that no hole or gap appears anywhere, provided that a space of two fingers is left at the top end of the cask, which must be filled with Spiritus Salis that has imbibed good and pure dissolved salt, so that the butter is thoroughly covered, and with all air excluded, it may be kept beautiful and flavorful for a long time. Before placing this on the table, remove it from the cask with a clean wooden spoon, not an iron one, and first wash it with pure and clear water if you do not want it to retain the acidity of the Spiritus Salis.

Behold an even better method. Fresh butter placed over embers melts gradually and is covered with much foaming cheese, and that foam is removed with a suitable spoon. After all the foam is removed, it remains in the pot like clear and limpid oil; from this, it must be poured slowly into another vessel so that the impurities remain at the bottom where they have settled. The cold butter does not yield in the least to yellow wax in its color, but it is softer than is proper; therefore, at the proper time, it must be stirred