On 08/09/13 15:27, Nick Maclaren wrote:
In article ,
Tom Gardner wrote:

Somewhere in this house, I have a Ministry of Food booklet from the
1940s which describes the preservation of garden produce ("Dig For
Victory" and all that). It describes the bottling of fruit, and
says that bottling vegetables at home should not be attempted, as
it needs to be done under pressure.

As supporting evidence for that...

"Home Preservation of Fruit and Vegetables" by Fish.& Food,Min.of
Agriculture (Jul 1989) isbn 0112428649, first published in 1929

That's almost certainly an updated version of the same booklet.

From the forward... "In the sixty years since it was first
published by the Long Ashton Research Station[RIP] and MAFF
[it] has been revised and updated on many occasions. Encouraged
and supported by the National Federation of Women's Institutes..."

Perhaps not even updated very much :-)

Freezing is a "modern method" of preservation, and microwave
cookers shouldn't be used for jam, except for softening fruit.

But then how much of this has changed since 1929? The basics
were well understood by then.