In article o.uk,
Dave Liquorice 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.

Were domestic pressure cookers easily available during the war? I
have a feeling that they may have existed before but like a lot of
things disappeared during and only reappeared in the early 50's.

Dunno. That could well be - they certainly weren't something that
every house had, even in the 1960s.

I agree there has been some mis-information in this thread,
bottling/canning really combines several preservation processes
depending on what is being bottled/canned. Broadly these processes
are heat treatment, hermetic sealing and sugar/acidity level.

The heat treatment and sugar acid levels are interrelated in that if
you have high sugar (jams etc) or high acid level (ph4.6 according
to wikipedia) you don't need to have heat treatment above 100C. If
the sugar content is low / acidity ph4.6 then you ought to have
high temperature treatment and the way to do that is in a pressure
vessel of some sort.

Yes. Or salt, of course.

Trying to use the food type to define the bottling process required
can lead to an incorrect process being used.

Except that virtually all fruit grown in the UK have a fair amount
of acid. Even strawberries have SOME - we don't have any fruit
like bananas or avocados that are grown and eaten, that I can
think of.


Regards,
Nick Maclaren.

In article ,
Tom Gardner wrote:

I forgot to say "Thank you" for posting that data.

Regards,
Nick Maclaren.

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.

On 08/09/13 15:44, Nick Maclaren wrote:
In article ,
Tom Gardner wrote:

I forgot to say "Thank you" for posting that data.

You're welcome - it was my pleasure to re-acquaint
myself with the book. Things like using a trivet (in a
saucepan of hot water) to keep the glass off the
bottom, but if you don't have a trivet then you can
use rolled up newspaper. Really appeals to the "this
is what you are trying to achieve; you can do it via
conventional and unconventional mechanisms" that I
see in the best engineering.

Must try and make some sauerkraut...
(Keep the cabbage at 21C-27C for 2-3 weeks; rats - should
have done it last month!)

"Janet" wrote in message
t...
In article ,
says...

You could do it by putting your filled jars in a pressure cooker.
You would need to be certain all parts of the contents were heated
through.

Have you never used a pressure cooker?

You would need to be certain they were cool (unpressurised before opening
the pressure cooker.

Nobody who has ever used a pressure cooker would find it remotely
difficult to depressurise or cool.

So even then a bit dodgy.

Using a pressure cooker is not in the least bit uncertain difficult or
dodgy; just unnecessary in this instance.


http://www.1900s.org.uk/1940s50s-preserving-fruit.htm
http://www.kilnerjar.co.uk/Preserving/guides/how-to-
preserve#.UixMLH8WYuc

Janet

Clearly you are one that needs to be made aware of the dangers.
If you rapidly depressurise a pressure cooker and there is a closed
container inside, the container may explode due to over pressure and/or
thermal shock.

"harryagain" wrote in
:


"Janet" wrote in message
t...
In article ,
says...

You could do it by putting your filled jars in a pressure cooker.
You would need to be certain all parts of the contents were heated
through.

Have you never used a pressure cooker?

You would need to be certain they were cool (unpressurised before
opening the pressure cooker.

Nobody who has ever used a pressure cooker would find it remotely
difficult to depressurise or cool.

So even then a bit dodgy.

Using a pressure cooker is not in the least bit uncertain difficult
or
dodgy; just unnecessary in this instance.


http://www.1900s.org.uk/1940s50s-preserving-fruit.htm
http://www.kilnerjar.co.uk/Preserving/guides/how-to-
preserve#.UixMLH8WYuc

Janet

Clearly you are one that needs to be made aware of the dangers.
If you rapidly depressurise a pressure cooker and there is a closed
container inside, the container may explode due to over pressure
and/or thermal shock.



Careful here!
Janet is the expert on everything. It likes to think so, but nope it is a
dope.

Baz

In article ,
says...

"Janet" wrote in message
t...
In article ,
says...

You could do it by putting your filled jars in a pressure cooker.
You would need to be certain all parts of the contents were heated
through.

Have you never used a pressure cooker?

You would need to be certain they were cool (unpressurised before opening
the pressure cooker.

Nobody who has ever used a pressure cooker would find it remotely
difficult to depressurise or cool.

So even then a bit dodgy.

Using a pressure cooker is not in the least bit uncertain difficult or
dodgy; just unnecessary in this instance.


http://www.1900s.org.uk/1940s50s-preserving-fruit.htm
http://www.kilnerjar.co.uk/Preserving/guides/how-to-
preserve#.UixMLH8WYuc

Janet

Clearly you are one that needs to be made aware of the dangers.
If you rapidly depressurise a pressure cooker and there is a closed
container inside, the container may explode due to over pressure and/or
thermal shock.

Who said "rapidly depressurise a pressure cooker"?
Take it off the heat. Do nothing. That's how easy it is.
The pressure cooker will depressurise all by itself.

Janet

On Sun, 8 Sep 2013 20:41:55 +0100, Janet wrote:

Clearly you are one that needs to be made aware of the dangers.
If you rapidly depressurise a pressure cooker and there is a
closed
container inside, the container may explode due to over pressure
and/or
thermal shock.

If a closed container in a pressure cooker hasn't already exploded...

AIUI the containers are not sealed until they have been through the
high temperature/pressure process and cooled to be accessable at room
pressure.

Any lids etc also need to have gone through the high temp/pressure so
presumably they are loosely fitted to keep most of the water/steam
out of the product and tightly fitted whilst everything is still very
hot.

Who said "rapidly depressurise a pressure cooker"?
Take it off the heat. Do nothing. That's how easy it is.
The pressure cooker will depressurise all by itself.

Once you take the weights off... Will the pressure drop to
atmospheric in a sensible time scale once removed from the heat and
weights left on? I guess you let it cool 'till it stops hissing from
the weights then keep trying to lift the weights without it blowing
too much, FSVO "too much" steam out.

I've no great experience of pressure cookers, My Mum didn't like 'em
so we never had one at home.

--
Cheers
Dave.

In article o.uk,
says...

On Sun, 8 Sep 2013 20:41:55 +0100, Janet wrote:


Who said "rapidly depressurise a pressure cooker"?
Take it off the heat. Do nothing. That's how easy it is.
The pressure cooker will depressurise all by itself.

Once you take the weights off... Will the pressure drop to
atmospheric in a sensible time scale once removed from the heat and
weights left on?

Yes. A few minutes; not hours .

I guess you let it cool 'till it stops hissing from
the weights then keep trying to lift the weights without it blowing
too much, FSVO "too much" steam out.

If I DO want the PC to depressurise quickly, I take it off the heat
and slip a knife point through the ring on the weight and tilt it,
which releases steam fast. Once it stops hissing you lift off the weight
and can open the lid.

Janet.

On 9/9/2013 4:01 PM, Martin wrote:
On Mon, 9 Sep 2013 18:07:35 +0100, Janet wrote:

If I DO want the PC to depressurise quickly, I take it off the heat
and slip a knife point through the ring on the weight and tilt it,
which releases steam fast. Once it stops hissing you lift off the weight
and can open the lid.

I use a fork or put the pressure cooker in the sink and run cold water
over it.

My doesn't have weights, but it does have a quick-release setting.

On 9/10/2013 5:30 AM, Martin wrote:
On Mon, 09 Sep 2013 19:22:31 -0400, S Viemeister
wrote:

On 9/9/2013 4:01 PM, Martin wrote:
On Mon, 9 Sep 2013 18:07:35 +0100, Janet wrote:

If I DO want the PC to depressurise quickly, I take it off the heat
and slip a knife point through the ring on the weight and tilt it,
which releases steam fast. Once it stops hissing you lift off the weight
and can open the lid.

I use a fork or put the pressure cooker in the sink and run cold water
over it.

My doesn't have weights, but it does have a quick-release setting.

Our current pressure cooker is a Fagor bought in Lidl. It doesn't have
weights either. For decades we used a Prestige, which does use
weights.

Mine is also a Fagor, bought in Costco.

On 07/09/2013 14:13, Baz wrote:
(Nick Maclaren) wrote in
:

In article ,
David Hill wrote:

I was wondering, instead of wasting gas and electricity to
sterilize the jars, if citric acid and sodium bisulphite(as in
winemaking sterilization) would do the trick.
I do bottle some things when I have the oven on and cooking.

No, they wouldn't. Not even remotely.

That combination kills things like acetobacter, lactobacter etc.,
few of which sporulate. If you are going to store non-acid foods
anaerobically, you need to either kill some very tough spores or
prevent them from growing. That is why salting, smoking etc. were
and are used to preserve such foods.

I am sure that in the beginning Baz said he was going to bottle fruit
and veg.
Where have you got this obsessive idea that he is going to bottle fish
and meat?
For fruit I've used a combination of Sodium Metabisulphite and boiling
water to clean the jars, as I do for Jam, just has foul vapour.

I have not, but you seem to have an obsessive delusion that all
vegetables are high in acid. Since you seem to have trouble with
this:

MOST VEGETABLES DO NOT CONTAIN ENOUGH ACID TO STOP CLOSTRIDIUM
BOTULINUM FROM GROWING.

MOST FRUITS DO, HOWEVER, AND *T*H*E*R*F*O*R*E* EXPERIENCE WITH
FRUIT IS *I*R*R*E*L*E*V*A*N*T*.

THE RISK OF BOTULISM FROM BOTTLING VEGETABLES IS VERY LOW.

BUT THE RISK OF DEATH IS *V*E*R*Y* HIGH IF IT DOES HAPPEN.

IT IS PROBABLY *H*I*G*H*E*R* THAN FOR MEAT AND FISH, FOR
SEVERAL REASONS.


Regards,
Nick Maclaren.


Capitals are regarded as shouting.
Perhaps you can set your keyboard to whispering.
Only joking.

But can I bottle.........
Joking again.

He is *D*E*A*D*L*Y* serious. If you get the pH wrong then herbs or
garlic in oil can be an almost perfect way to create the right anaerobic
conditions that allow any botulinum free reign to grow. Any vegetables
with even slight soil contaminiation may be a vector.

It is one of those recent DIY grow your own "health food" home bottling
fads that has caused several nasty incidents. Fatalities are ~50% if not
treated quickly and about 8% with early diagnosis and treatment.

US where home canning is more popular have more of a problem with it
than we do in the UK. Acidic environments like preserved fruit are
fairly safe. Although nothing is guaranteed branded products that you
would expect to be safe on multiple levels have failed in the past eg

http://www.bbc.co.uk/news/uk-scotland-15712910

(I was looking for the one on home preservation and pH guidelines)

US sites have the most detailed information, but I do recall a home
garlic/chilli oil one in the UK not so long ago.

http://www.ext.colostate.edu/pubs/foodnut/09305.html

Surprisingly over there asparagus is the main culprit. I reckon it is
sacrilege not to eat them poached immediately fresh out of the ground!

--
Regards,
Martin Brown

On 09/09/2013 10:38, Dave Liquorice wrote:
On Sun, 8 Sep 2013 20:41:55 +0100, Janet wrote:

Clearly you are one that needs to be made aware of the dangers.
If you rapidly depressurise a pressure cooker and there is a
closed
container inside, the container may explode due to over pressure
and/or
thermal shock.

If a closed container in a pressure cooker hasn't already exploded...

It should be mostly OK provided that the pressure in the container is
coupled to the pressure in the autoclave the boiling point of the water
inside it will also be raised. Conversely the water inside the container
will boil until it matches the working pressure in the cooker.


AIUI the containers are not sealed until they have been through the
high temperature/pressure process and cooled to be accessable at room
pressure.

Any lids etc also need to have gone through the high temp/pressure so
presumably they are loosely fitted to keep most of the water/steam
out of the product and tightly fitted whilst everything is still very
hot.

I think for home canning it is supposed to be fully sealed and then
aggressively pressure cooked. Not sure how well Killner jars would stand
up to it. We blanch and then freeze pea & bean gluts.

Who said "rapidly depressurise a pressure cooker"?
Take it off the heat. Do nothing. That's how easy it is.
The pressure cooker will depressurise all by itself.

Once you take the weights off... Will the pressure drop to
atmospheric in a sensible time scale once removed from the heat and
weights left on? I guess you let it cool 'till it stops hissing from
the weights then keep trying to lift the weights without it blowing
too much, FSVO "too much" steam out.

I've no great experience of pressure cookers, My Mum didn't like 'em
so we never had one at home.

Sudden decreases in pressure are a very bad thing as flash boiling
inside some thick goupy stew or soup inside one is a disaster!

I have distant recollections of conical fountains of scalding soup
flying up into the air plastering the kitchen ceiling and bouncing all
over at my aunts. They are fine if used correctly but there is scope for
considerable excitement if you make a mistake at high pressure.

ISTR some kind of emergency pressure release system triggered on it.

--
Regards,
Martin Brown

On 10/09/13 12:09, Martin Brown wrote:
On 09/09/2013 10:38, Dave Liquorice wrote:
On Sun, 8 Sep 2013 20:41:55 +0100, Janet wrote:

I've no great experience of pressure cookers, My Mum didn't like 'em
so we never had one at home.

Sudden decreases in pressure are a very bad thing as flash boiling inside some thick goupy stew or soup inside one is a disaster!

OTOH, flashing water into steam *may* be a good way of disrupting
structures and possibly cells. Might be useful when turning
fish/meat/veg into stock.

Easily done by lifting up the weight - and watching the steam
spray 2ft horizontally from each of four holes. Good for startling
guests/kids

I'd get worried if there *wasn't* any steam coming from weight,
because...

I have distant recollections of conical fountains of scalding soup flying up into the air plastering the kitchen ceiling and bouncing all over at my aunts. They are fine if used correctly but there
is scope for considerable excitement if you make a mistake at high pressure.

The next stage on mu cooker is a rupture plate under the
lid's handle, so the contents wouldn't hit the ceiling
but would probably splatter sideways.

ISTR some kind of emergency pressure release system triggered on it.

In article ,
Tom Gardner wrote:
On 10/09/13 12:09, Martin Brown wrote:
On 09/09/2013 10:38, Dave Liquorice wrote:
On Sun, 8 Sep 2013 20:41:55 +0100, Janet wrote:

I've no great experience of pressure cookers, My Mum didn't like 'em
so we never had one at home.

Sudden decreases in pressure are a very bad thing as flash boiling inside some thick goupy stew or soup inside one is a disaster!

OTOH, flashing water into steam *may* be a good way of disrupting
structures and possibly cells. Might be useful when turning
fish/meat/veg into stock.

Easily done by lifting up the weight - and watching the steam
spray 2ft horizontally from each of four holes. Good for startling
guests/kids

Mopping up the stock before use is a little fiddly :-)


Regards,
Nick Maclaren.