[Kleftiwallah]

Knocking up a batch of greengage jam and it calls for a knob of butter (apparently it 'kills' the froth on the top of the jam before bottling.  I've searched diligently but I cannot find anywhere that tells you how big a knob of butter it should be!      Cheers,    Tony.

[rhysdad]

Knocking up a batch of greengage jam and it calls for a knob of butter (apparently it 'kills' the froth on the top of the jam before bottling.  I've searched diligently but I cannot find anywhere that tells you how big a knob of butter it should be!      Cheers,    Tony.

I usually stir in a teaspoon or so, say 5/10g piece, after you've let the jam settle back down to a simmer and NOT when it's still on a boil. That's usually always sufficient.

[Kleftiwallah]

Thanks for that, 50p it is then.      Cheers,    Tony.