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Rules of jelly thumb?

Yesterday we had lamb chops, and lacking anything interesting to dress them with, I made a lemon and mint jelly.

I took two lemons, zested and squeezed them, added some water and some sugar and boiled for a bit. Then I tasted and it seemed a bit tart so I put some more sugar in. Finally I added piles of chopped mint and boiled a bit more.  At that point it set if I dripped it onto a cold plate, so I strained out the mint and zest and stuck it in the fridge to congeal.  It was good.

Thing is though, I have no idea if I could have made a larger quantity of less acidic jelly if I'd put more water in, or if it would then just have been a syrup.  Or if I could have got away with one lemon.  I have a vague feeling that this has something to do with the pectin content of the lemons, but how one estimates that, I do not know.

Does anyone know about the theory behind jam and jelly recipes?   I'm OK with making stuff from a recipe, or even improvising based on a recipe -  but would like to know more about how the gelling bit works so I can be more freeform about my jellies in future!  Google is not being helpful today: it gives me recipes, not an understanding of the principles behind them.


( 11 comments — Leave a comment )
15th Jun, 2009 12:49 (UTC)
From your description, it looks like you extracted some of the pectin from the lemon. Pectin is a nice molecule which gels with the help of ions like Calcium (also sodium, potassium or other cations).

Corn starch, on the other hand, gels using a different mechanism. When you add corn starch (or any starch) to a roux or as a thickener, it swells, then breaks apart with accompanying changes in viscosity with temperature. But I digress.

So, in order to control the viscosity of your jelly, you need to extract more pectin from the citrus peel/zest (rather than the juice) and taking care not to get the bitter pith involved. For the most part, pectin is hot-water soluble. There's a bunch of chemistry involving the methoxy content of pectin which controls gelation behavior but for all practical purposes what you're doing will work.

15th Jun, 2009 13:42 (UTC)
Re: gelation
Hmm, that helps with formulating search queries, thanks.

I think what I need to know is:
- how much pectin (on average) per zest of standard lemon
- how much acid needed to gel that much pectin
- how much liquid will that much pectin and acid gel.

Searching for that I found a rough figure of 3 grams of pectin per lemon,

and a recommended ratio of : 1 teaspoon lemon juice: 3 tablespoons water : 1/2 teaspoon of sugar.

What frustrated me a little about this is that with most recipes, there is a basic underlying ratio to get a certain effect, then you add stuff or adjust things (eg, basic sponge recipe).

Whereas with jellies and jams you seem to get lots of recipes saying 'for best results follow the recipe' or even, infuriatingly, 'the ratio of fruit, sugar, acid and pectin must be correct' but not explaining how the recipe was compiled, or how 'correct' can be achieved.

Or at least, a reasonable, close-enough-for-jazz varient of 'correct' anyway. I don't want to win prizes, just make stuff that is edible!

I suppose that's down to the variability of fruits. I'm far too lazy to have bottles of specialised stuff like pectin around the place so improvising from whatever fruit comes to hand is easier...
16th Jun, 2009 03:02 (UTC)
Re: gelation
I was trying to think of gelling substitutes for pectin but they are all extracts just like commercially available pectin (seaweed gels, konjac root, tapioca etc).

You are right about the variability of fruits. Nature is a wonderful randomizer.

Apples have a lot more pectin in their flesh so perhaps you could use the hot water extract as a pectin subsititute. Apples may or may not have a strong taste, though.

One of my baker friends once mentioned a 5/7 ratio of pectin/sugar as a rule of thumb. I don't know if this is accurate or even if I remembered it correctly.

Good luck!

16th Jun, 2009 03:05 (UTC)
Re: gelation
and I should read the rest of the commentds before replying. :)
16th Jun, 2009 20:06 (UTC)
Re: gelation
One of the main problems is you never know how much pectin is in the fruit as it always varies, so even if you think you have the correct ratio and the fruit is one that is supposed to be high in pectin, the jam or jelly might still never set. But certainly if you're using lemons you shouldn't go far wrong, as citrus fruit is very high in pectin. My Mum always added a the juice and zest of a lemon to her strawberry jam until she discovered jam sugar.

I don't like the bottled pectin, it always makes stuff taste earthy to me, but that may just be my palate. I do like jam and preserving sugar for their consistent results though. But of course you have to have those lying around to be able to use them, so lemons are probably a better bet for the impromptu jam/jelly session :-)
17th Jun, 2009 10:04 (UTC)
Re: gelation
McGee on the history and science of cooking is a great book for this sort of thing.
15th Jun, 2009 14:25 (UTC)
Strictly speaking, they were lamb steaks, not chops. And very nice too.
15th Jun, 2009 15:19 (UTC)
Citrus fruit pips are very rich in pectin, which is why when making marmalade you stick the pips and pulp in a muslin bag and boil them up together with the juice and rind. (The bag is so you can get them out again, it doesn't add anything to the flavour).

My grandmother used to make mint jelly with a base of apples, which are also very rich in pectin. This would probably mean you could dispense with a lot of water & sugar. At a guess, something like "boil apples to a pulp with a bit of sugar, lemon juice, and the pips or perhaps all the rest of the lemon in a little bag". But as I've only one apple in the house, I'll leave you to do the experimenting.
15th Jun, 2009 15:43 (UTC)
Wrong time of year for apples at the mo, but I often make bramble jelly on a base of apples in the autumn, and yes, that it pretty much how it goes: that was what I based the lemon jelly on. You do need some sugar to make it palatable though (or I think so anyway), the greener apples are the more pectin-y ones so otherwise it ends up very sharp.

I just left the pips in when squeezing the lemons, as I put it all through a sieve at the end anyway.
31st Jul, 2009 01:18 (UTC)
wellinghall was correct, McGee does discuss the theory of pectin gelling, but only briefly, and mostly says the 'correct' amounts are impossible to test for in ordinary home-kitchen conditions. I found it not terribly helpful.

I have a long history of snagging any interesting cookbooks up at yard sales, garage sales, church sales, and the occasional used book store (not a lot of those up here in the hinterlands), with a particular interest in pickling and preserving. One of the few I've bumped into is "Gourmet Preserves Chez Madelaine" by Madelaine Bullwinkel. It has an entire chapter on the theory and practice of jellying, without the use of commercial pectin, including how to test for pectin levels in the fruit you have on hand.

It was originally published here in the States in '85 (Contemporary Books, Chicago IL, ISBN 0-8092-5482-4), but a trade paper edition came out in 2005 (Surry Books, Chicago IL, ISBN 1-57284-078-4, distributed by Publishers Group West), so it may now be alittle easier to find. If you're interested but can't find a copy on your side of the pond, let me know. I came across a copy of the original hardback last year, so my shiny paperback is more or less a spare now.
2nd Aug, 2009 08:46 (UTC)
oooh, thanks for the recommendation (and the offer of spare book!) Copies do seem to be available here second hand, so I shall snag one of those and save you posting it.

I should probably check my local independent bookshop before buying online, we are lucky to have a couple of quite good ones (one mostly new books, one second hand).
( 11 comments — Leave a comment )

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