Is it possible to make knox gelatin stay a gel in warmer tempratures?
July 13, 2010 6:03 AM Subscribe
Is it possible to increase the temprature in which home made ballistics gelatin (made with knox gelatin) reverts back to a liquid? Possibly substituting a different liquid other than water or adding some household item?
Just interested in testing with this gel in a warmer environment thats not so friendly to gel's staying gel's.
Just interested in testing with this gel in a warmer environment thats not so friendly to gel's staying gel's.
Response by poster: Yeah I couldn't think of anything either.
posted by Chamunks at 6:13 AM on July 13, 2010
posted by Chamunks at 6:13 AM on July 13, 2010
Response by poster: I mean other than thickening it more by using less water in the mix. Would that theoretically make the melting temperature much higher?
posted by Chamunks at 6:32 AM on July 13, 2010
posted by Chamunks at 6:32 AM on July 13, 2010
could you make it with Agar Agar instead - that doesn't melt with heat.
posted by JPD at 6:35 AM on July 13, 2010
posted by JPD at 6:35 AM on July 13, 2010
Seconding agar. It is used for making dental molds, so it's good at least as high as body temperature.
posted by alms at 6:52 AM on July 13, 2010
posted by alms at 6:52 AM on July 13, 2010
From my reading of the pertinent section of On Food and Cooking, increasing the gelatin concentration will just give you a gel that's firmer and rubberier when cold, but still melts at the same temperature. Basically, the protein molecules that are in gelatin change shape around 40°C; below this temperature they can lock together to form a matrix that holds the liquid in place, but above this temperature they can't. As JPD suggests, you might try agar; from McGee's descriptions, you might also look into kappa-carrageenan or gellan gum.
posted by Johnny Assay at 7:01 AM on July 13, 2010 [1 favorite]
posted by Johnny Assay at 7:01 AM on July 13, 2010 [1 favorite]
Aren't Agar and Carrageenan basically the same thing? Gelling agents derived from red seaweed?
posted by JPD at 7:06 AM on July 13, 2010
posted by JPD at 7:06 AM on July 13, 2010
Agar is derived from red algae; carrageenan is derived from red seaweed. There are some nerdy chemical-y details about the difference in the agar Wikipedia entry.
posted by bcwinters at 7:23 AM on July 13, 2010
posted by bcwinters at 7:23 AM on July 13, 2010
When I was a kid and was intensely interested in gelatin (yeah, I'm weird), I found that repeated melting and cooling made the temperature at which the gelatin melted raise a bit each time. The volume remained about the same (except for a few experiments in which it got leathery).
I am pretty sure, though, that most of the changes you make will also make the particular mechanical properties of the ballistic gelatin less ballisticy.
posted by adipocere at 7:29 AM on July 13, 2010
I am pretty sure, though, that most of the changes you make will also make the particular mechanical properties of the ballistic gelatin less ballisticy.
posted by adipocere at 7:29 AM on July 13, 2010
Following up on valkyryn thought, if the agar doesn't work, you could try to do a sort of localized cooling around the gelatin block itself. I'd probably go with some kind of lightweight wood frame around the outside holding cooling packs (even something as low tech as a ziplock baggy of ice) as close as possible to the gel.
It's still going to melt, but it might increase the lifespan enough to make it usable for your needs.
posted by quin at 1:19 PM on July 13, 2010
It's still going to melt, but it might increase the lifespan enough to make it usable for your needs.
posted by quin at 1:19 PM on July 13, 2010
Response by poster: adipocere do you have any more information on the heating and cooling like any tempratures and the mix ratio you used sorts of things like that?
posted by Chamunks at 5:26 PM on July 13, 2010
posted by Chamunks at 5:26 PM on July 13, 2010
I've looked at agar for a different gelatin-related product, but where can you buy it?
posted by DU at 9:51 AM on July 14, 2010
posted by DU at 9:51 AM on July 14, 2010
Response by poster: Seems like agar is easiest to buy online in powder form. I just wonder how difficult it would be to get agar to the same consistancy of knox gelatin setup as ballistics gel without having random bits of mold spores colonizing on it.
posted by Chamunks at 1:07 AM on July 15, 2010
posted by Chamunks at 1:07 AM on July 15, 2010
How long do you need it to keep? I would think gelatin would get colonized too--it's a foodstuff, after all. Protein.
posted by DU at 4:17 AM on July 15, 2010
posted by DU at 4:17 AM on July 15, 2010
agar will gel faster then gelatin will. I would be more concerned with how it handles in use. Gelatin will melt from the force of impact, agar will shatter. I have no idea how that would impact using one over another but something to keep in mind
posted by JPD at 5:14 AM on July 15, 2010
posted by JPD at 5:14 AM on July 15, 2010
Response by poster: Would a mixture between agar and gelatin would meet me half way without changing the recipe too much?
posted by Chamunks at 2:32 PM on July 17, 2010
posted by Chamunks at 2:32 PM on July 17, 2010
This thread is closed to new comments.
posted by valkyryn at 6:10 AM on July 13, 2010