mleku on Nostr: my mother was a huge fan of pressure cookers. they cook so fast because of the amount ...

my mother was a huge fan of pressure cookers. they cook so fast because of the amount of heat water holds and the fact that it gets above boiling point. in an open pot it would get to about 90-95'C but in a PC they can get over 120 and that is a lot more increase in energy than you realise (it's maybe 20x as much or some number like this).

also i saw this great little DIY how-to make a waterproofing treatment for sheets that made them superior to commercial tarps, and he said "use the lowest setting so you don't make the wax/oil mix smoke up" and while it may seem like it's great it's gonna be quicker, higher temperatures can damage the proteins more. my mother never made jam in my memory, but mostly what she cooked in it was meat and high protein plant foods, and those are fine to heat well past 150-200'C. pectin, however, i don't think it will gel up as well if you overheat it.

i had to ask claude to make my info more precise

Pressure cookers typically reach around 120°C (250°F) compared to 100°C (212°F) at atmospheric pressure. This does affect pectin, but not necessarily in a damaging way:

What happens to pectin at high temperatures:

- Pectin chains can undergo hydrolysis (break down) at elevated temperatures, especially in acidic conditions

- Extended exposure to high heat reduces pectin's gelling ability

- The damage is time-dependent — short cooking times minimize degradation

Why pressure cookers still work for marmalade:

1. Reduced cooking time — The higher temperature dramatically speeds up softening the peel, so total heat exposure may actually be less than traditional methods

2. Two-stage approach — Many recipes pressure cook the fruit first to soften it, then add sugar and pectin for a brief open-pot boil to reach setting point

3. Pectin addition timing — Adding pectin after pressure cooking avoids exposing it to the elevated temperatures

Practical advice:

- Use pressure cooking only for the initial softening of citrus peel

- Release pressure, add sugar and pectin, then boil briefly at normal pressure to set

- If using the fruit's natural pectin, slightly increase the amount of high-pectin components (pith, seeds in a muslin bag)

The technique works well — you get tender peel in 10-15 minutes instead of 1-2 hours, with minimal pectin loss if you time it right.

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so, yeah, it's too much for getting the pectin to gel right, you may find this is very liquid after it sits in the fridge.