Pressure Cooking?

[ChrisGreaves]

Mum used a pressure cooker, and I remember the operation.
Now I have stumbled across a recipe that calls for pressure-cooking:-

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Well. I don't own a pressure-cooker.
Nor do I have those little 1-cup Mason jars.
But i do have a collection of yeast jars which are about the right size (two inches diameter and about as high), which have metal lids with thin rubber gaskets.
I use all sorts of jam-jars and pickle jars for preserving, so nothing new here.

Question 1: When I preserve fruit and veg in a boiler, the lids are screwed finger-tight, and i think that as they come to the boil, they are under pressure to the extent that the water vapour has to force its way out of the jar, that is, there must be excess pressure to expel the vapour. So does this count as "pressure cooking"?

Question 2: Whenever i see something esoteric in a recipe (such as "hacksaw the lamb leg bone in two places") I suspect it is mere circumstance. In the cheesecake recipe, maybe the originator was using pressure-cooking to shave ten minutes off the cooking time (I'm retired, so what do i care about ten minutes), and in the leg-of-lamb case, 'because my mum always did that, because here mum always did that", because grandma had only a small roasting pan to fit in the small oven. OK, the question part: Is pressure-cooking an essential aprt of cheesecake making?

Question 3: Is there anything in cooking where a pressure cooker is a necessity, as distinct from a pleasant adjunct to the process?

Ta ever so
Chris

[Claude]

Well. I don't own a pressure-cooker.

We've got a Kuhn Rikon Bluetooth pressure cooker, I can highly recommend it !

Question 3: Is there anything in cooking where a pressure cooker is a necessity, as distinct from a pleasant adjunct to the process?

Necessity AFAIK no, desirability yes: As an example, a Berner Platte which I have been cooking for centuries, albeit not since 1798, is so much tastier if done in a pressure cooker as opposed to slow cooking or micro-waving the dish.

[BobH]

Chris,
We do cheesecake in the oven using a bain marie.
We don't own a pressure cooker.

[PJ_in_FL]

We have an electric pressure cooker similar to an Instant Pot. We actually use an Instant Pot cookbook for recipe suggestions.

May not be a necessity, but I have yet to find something out of that pot that wasn't wonderful. We drop whole sectioned cauliflower and cook for 3-5 minutes as opposed to baking in the oven.

A very nice feature of pressure cooking is to use lower quality meats, good cuts, just not prime or choice grade. After cooking these are as tender as the best steaks.

Chris, regarding your question about the pressure in the jars in a boiler, it has to be just barely above room ambient because the pressure is constantly equalizing. Anything more and the glass would be in danger of breaking.

[Jay Freedman]

The whole point of a pressure cooker is that the pressure inside the vessel is considerably higher than one atmosphere, which causes the boiling point of the water to be higher than 100°C. If the temperature is, say, 150°C, that speeds up the cooking. If steam is escaping from your jars, as PJ pointed out, the pressure in the jars isn't high enough to make a difference in the temperature.

[ChrisGreaves]

... the pressure in the jars in a boiler, it has to be just barely above room ambient ..

Admirable Logic, my friend!
(Why didn't ***I*** think of that ? .....)

The regular mason jars are somewhat thick, but the bread yeast jars are thinner-skinned. (I can see where this is going )

Were I to measure them, I suspect that the mason jars can sustain a higher pressure than the yeast jars.
Which would mean that the effect of pressure in the yeast jars(for my individually-packaged cheesecakes) would not benefit, significantly from the pressure.

Oh well, it was fun asking.

I suppose too that this means that when I use regular mason jars to preserve meat sauces, fruits and so on, I am using a significantly higher temperature than mere boiling-point.
So I would expect an increased probability of killing off a greater range/variety of bacteria.

Cheers
Chris

[ChrisGreaves]

The whole point of a pressure cooker is that the pressure inside the vessel is considerably higher than one atmosphere, which causes the boiling point of the water to be higher than 100°C. If the temperature is, say, 150°C, that speeds up the cooking. If steam is escaping from your jars, as PJ pointed out, the pressure in the jars isn't high enough to make a difference in the temperature.

Thanks Jay.
I know about the Pressure Cooker itself; we almost lived out of it when i was a kid, boiling bones for the dog, cooking lettuce (my Dad was a bit of an idiot) etc.
We lived in a galvanised-iron house with a wood-stove, so I suspect a large part of the idea was to reduce the time spent emitting cooking heat.
It is more of a space consideration that sees me, today, avoiding too many kitchen gadgets. That and the small size of the family (grin)

Re the bread yest jars: thanks to you and PJ my brain is back on track.
temporarily.
Cheers
Chris

[DaveA]

Pressure cooking was also needed (required) at higher heights in the mountains.
As one could not even boil potatoes or even pasta, it would take forever.
My mon and other cooks in the family had several cookers and there seems that everyday one was in use if not a couple.