Does altitude affect Jelly (Jell-o) setting? - Page 2

ecb · #21 19.01.2011, 10:08

	Quote:	Ittigen
	Please just read the post before yours.

It was posted whilst I was writing my post, so it was not showing until after I posted.

Shorrick Mk2 · #22 19.01.2011, 10:16

Vodka Jello shots everyone.

Lausannebrit · #23 19.01.2011, 13:16

	Quote:	RandV
	On the past three attempts on making Jelly (Hartley's from the uk), the jelly has not set very well. Much to my children's disappointment - the jelly came out of the mould and just spread out on the plate. We only live at 600m so not very high, but I never had any problem in low-lying London. Any tips?

Where did you buy your UK jelly from?

I've bought Hartley's jellies from Globus in Lausanne and had similar results to your description.

I eventually figured out why... They'd covered over the English instructions on the packet with a sticker that gives the instructions in French... only they were wrong.

The amount of liquid had been incorrectly translated from "make up to 1 pint" to "add 1 pint", meaning that I had more liquid than I should have had, and thus an incorrect solution which did not set as solidly as I was expecting.

Worked fine once I went back to the English instructions..

Leni · #24 19.01.2011, 13:30

You didn't add any fruit did you?
The enzymes in kiwi or pineapple can prevent jelly from setting properly.

PaddyG · #25 19.01.2011, 13:42

Just add some mercaptoethanol

RandV · #26 19.01.2011, 20:30

	Quote:	HeatherM
	The lengths of the protein molecules in gelatin don't change with heating or boiling, it takes a lot more than 100 degrees to break apart a protein molecule. To make jelly from gelatin, you need to denature the proteins in gelatin; in other words, heat them up so they change their conformation and essentially melt or unfold into long strings. The denatured gelatin has a much higher affinity for water than undenatured gelatin. As the denatured gelatin slowly cools, water molecules are trapped by these strings of gelatin, and you end up with jelly. (Yes weejem, it is a hydrocolloid.) The process of protein denaturation is dependent on both temperature and time. The less hot your water is, the longer it will take for gelatin to fully denature. So if your water is boiling at 95 instead of 100, I'd advise, as others suggested, simply boiling the mixture for an extra minute or two before allowing it to cool. That should work fine. If you're worried about loss of liquid by boiling it in a pan, simply measure the volume before putting it in the pan. Once you've finished boiling it, measure it again, and make up the difference with water. Regarding Mr. Zappa's assertion that gelatin will melt at 40 degrees, this may be true, but at that temperature the proteins will not be sufficiently denatured to trap enough water to make jello. (And for the record, I do actually do this at work. Denature proteins that is, not make gelatin. Tomorrow they're getting five minutes at 95 degrees C, which should be more than sufficient.)

Thank you all for your 'science' answers. My former A-level Biology students will be very disappointed that I have forgotten such simple BioChem - that's what having kids and trying to learn a new language does to the old grey matter!
I will initially try less water, if that fails I may attempt making 'real' jelly using gelatin sheets cooked for a little longer.

smackerjack · #27 19.01.2011, 20:36

I am at just under 1200m and if I make a jelly in a mould it does seem to be squidgy.
If I put it to set in the fridge in a basin - it is fine.
I do not think the altitude affects mine - but when I buy crisps or anything in a sealed packet and bring them here the altitude makes the bag just about burst

#28 19.01.2011, 21:06

So do you wear a 34B when you are down on the lake?

smackerjack · #29 19.01.2011, 21:33

Do you know - it's only in the last week that I realised you were a guy - always thought you were a girl - (now I know for sure

)

FrankZappa · #30 24.01.2011, 19:40

	Quote:	weejeem
	You don't need to apologise - I'd agree with you iof you were correct... Your reference to "melting point" shows that you're looking in entirely the wrong direction - the key point is not the melting point of gelatine, it's the length of the protein (gelatine) molecules when the mix cools down and changes from being solids in suspension in liquid, to being liquid in suspension in solid, and whether these molecules are sufficiently long to "hold" the water within the solid. Like I said, jelly (jello) is a colloidal suspension - IIRC, it's a reversible hydrocolloid, with a solid continuous medium and a liquid dispersed phase. Feel free to post some authoritative references to the contrary - to be fair, I was once wrong about something a few decades ago...

Well, you were certainly wrong this time. Also what you say above is rubbish. Gelatin gels are made up of short pieces of collagen structure in a continuous water phase. Time to reread or chuck out whatever old colloid textbook you thought you got this from.

Modesty forbids from citing my own papers

, so try this one:
All Gelatin Networks: 2. The Master Curve for Elasticity†

Christine Joly-Duhamel,‡ Dominique Hellio,‡ Armand Ajdari,§ and Madeleine Djabourov*‡
Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR ESPCI-CNRS 7636, and Laboratoire de Physico-Chimie Théorique, UMR ESPCI-CNRS 7083, 10, Rue Vauquelin, 75231 Paris Cedex 5, France

Langmuir, 2002, 18 (19), pp 7158–7166

#31 25.01.2011, 07:14

	Quote:	FrankZappa
	Modesty forbids from citing my own papers

Aw, go on! Seize this opportunity with both hands whilst you can - you won't get another chance to do it on EF for quite a while, I would suspect

jacek · #32 25.01.2011, 08:21

	Quote:	Lausannebrit
	The amount of liquid had been incorrectly translated from "make up to 1 pint" to "add 1 pint", meaning that I had more liquid than I should have had, and thus an incorrect solution which did not set as solidly as I was expecting. Worked fine once I went back to the English instructions..

Apart from laws of physics stated above, I always believed in RTFM rule, but I think in this case it was opposite and "translate the f...n manual" rule applies

In other disputable cases, the laws of physics always apply.