Tuesday, October 02, 2012

Patently Dried Vegetables.

I have been looking at some early British patents for various methods of food preservation, and want to share one of my finds with you today.

Until 1623, it was the privilege of the Crown to bestow (and presumably remove) monopolies. The Statute of Monopolies of 1623 aimed to limit this power, and allow inventors 14 years of exclusive right to the use and profits of their work. The statute remained in force until it was superseded by the Patent Law Amendment Act of 1852.

The first recorded British patent for a method of food preservation was in 1691. The recipients were Thomas Porter and John White, and although the details of their method were not given, it appears to have involved heat. It also appears that no commercial venture ensued from the successful application. Over the next hundred years or so, applications for ‘letters patent’ trickled in and were granted. Methods patented included those using spices, sugars such as molasses, salt, and chemicals such as saltpeter. The first patent for a canning method was that of Peter Durand in 1810, and for a freezing method, it was not until 1842 that Henry Benjamin and Henry Grafton obtained their grant for freezing fish in an ice and salt mixture.

I want to give you some details of one eighteenth century British patents which includes a ‘recipe’ of sorts.  In 1780, John Graefer, a horticulturalist/gardener was granted a patent for drying ‘a vegetable of the Brassica kind’. His application gives the following instructions, which seem to me to be a little vague in some important points:

“Put about one pound of salt into twenty gallons of water, and so in proportion for any greater or lesser quantity required: boil the same, and then put in the vegetables, where they must remain for the space of a minute or thereabouts, and then taken out and hung by seperate plants on lines or small hooks fixed to laths in a room previously impregnated with heat or fumigation, by means of a buzaglo or other stove, or a steam issuing through funnels, or by the natural heat of the sun or atmosphere, where they must continue until they are perfectly dry. In order to compleat them for exportation they must, after they are dried as above, be removed into a damp room, in order to imbibe a sufficient degree of humidity to prevent their crumbling or falling into pieces in the packing.”

Graefer believed that his invention would enable the vegetables to be kept for a year or more, without losing flavour or nutritive value. He also recognized its potential importance to the Navy, for the prevention of scurvy. I do not know if he ever made a commercial success of his method – that may be fodder for another post.

May you have some happy food-drying experiences.


Mizz Harpy said...

This sounds like a pretty good drying method compared to other old drying recipes I've found. I wouldn't let the leaves rehydrate though since moisture would allow mold growth but I guess that is why he adds salt to the blanching method.

The Old Foodie said...

I agree, Mizz Harpy, it is an odd instruction - to dry thoroughly then rehydrate slightly. too difficult to control, I think.
The patentee was ahead of his time though, I think. I dont think his idea got much attention.

Shay said...

The idea that dried vegetables could prevent scurvy was a fallacy that lasted for years.

In 1858 the US Army Medical Department was investigating an outbreak of scurvy at Ft Laramie, Kansas Territory (in what was later the state of Wyoming). The soldiers were succumbing to scurvy, said the medicos, because of a diet that included mostly dessicated vegetables.

Nonsense, replied the Commisary Department. Whatever was ailing Ft. Laramie, it couldn't possibly be scurvy. After all, the men had access to plenty of dessicated vegetables.

The Old Foodie said...

What is really amazing is that all the evidence was there from the second half of the eighteenth century that citrus could be used to prevent/treat scurvy - yet even the navies around the world were still allowing sailors (and in the case you mention - land soldiers) to suffer from it a hundred years later.