bmarley5780 Posted July 2, 2008 Posted July 2, 2008 I cant find cornstarch or corn flour in NC Food Lions... I have bought it there before (1 yr ago) and wasnt it near the cornmeal, flour and those items?
DIYMark Posted July 3, 2008 Author Posted July 3, 2008 DIYMark, be sure the "corn flour" is starch, and not actual corn meal. I think it was Pipipi who went through this recently, and the stuff he bought was corn meal. The corn starch should be snow white, as fine as talc, soft and fluffy. When baked, it turns golden, and has a bit of a funky smell. Sure is corn starch! that stuff is so air float its not funny. it made a nice corn starch cloud upon opening lol. Its super fine and white plus its has a funny smell once made too.
Swede Posted July 3, 2008 Posted July 3, 2008 DIYMark, be sure the "corn flour" is starch, and not actual corn meal. I think it was Pipipi who went through this recently, and the stuff he bought was corn meal. The corn starch should be snow white, as fine as talc, soft and fluffy. When baked, it turns golden, and has a bit of a funky smell.Sure is corn starch! that stuff is so air float its not funny. it made a nice corn starch cloud upon opening lol. Its super fine and white plus its has a funny smell once made too. Good deal! When I made my batch a while back, I found it took longer than I thought. I think I didn't spread it out thinly enough. But still, after 5 hours, even thick lumps were golden through to the middle. Starch is supposedly converted to Dextrin via acid catalysis. Next time I try it, I am going to crush some vitamin C tablets (starch plus ascorbic acid) and mix that powder thoroughly with the corn starch. It might hurry things up a bit, and give a more rapid and thorough conversion.
Pretty green flame Posted July 3, 2008 Posted July 3, 2008 Swede, adding ascorbic acid to starch won't do a thing, acidic catalysis takes place in solutions. Boiling starch in diluted HCl on the other hand will convert it into dextrine.
Swede Posted July 3, 2008 Posted July 3, 2008 Swede, adding ascorbic acid to starch won't do a thing, acidic catalysis takes place in solutions. Boiling starch in diluted HCl on the other hand will convert it into dextrine. Ah shoot. I thought perhaps there would be adequate residual moisture to get the ball rolling. Thanks for clarifying that.
Mumbles Posted July 3, 2008 Posted July 3, 2008 It never hurts to try I suppose. I believe there are some patents around using boric acid in the starch to create dextrins. I have to think that ascorbic acid may decompose at the cooking temperatures though. Most of the acid catalysis setups I've heard about pass the HCl vapor over the dextrin while it's cooking in the kiln. Obviously not possible with a home oven.
nickle Posted July 30, 2008 Posted July 30, 2008 This definately a newbie question I found the following referring to Dextrins; "In pyrotechnics, they are added to fire formulas, allowing them to solidify as pellets or "stars." My question is what chemical change takes place by baking the corn starch, other then drying it out. If all that is happening is drying why couldn't you just add the raw product (corn starch) to the comp? When making stars the water/alc mix thats is added just wets the dextrin making everything stick together. Plain corn starch will do the same thing or is there another reason (chemically)?
Mumbles Posted July 30, 2008 Posted July 30, 2008 It may cause it to stick together, but not with the kind of strength that dextrin will. Dextrins are water soluble short chain carbohydrates. The heat breaks up the longer chains into shorter units that can dissolve in water. A similar reaction takes place enzymatically when a seed sprouts into a plant, or when you are making beer. By making it water soluble, every part of it becomes sticky instead of just a few random side chains. The full binding strength can then be realized. It is somwhat like flour. You can add water and it will get a little sticky and hold it's shape upon drying. However if you boil it in water as in making wheat paste or gravy, it becomes substantially thicker and stickier. This is the same type of reaction. So plain starch may do the same thing, but far less effectively or with the same resiliency. Think of it like a reverse super glue. When it is in it's monomeric form it is very sticky, and able to be dissolved easily. When it dries, it polymerizes into a long chain that isn't nearly as sticky or soluble.
suedetrombone Posted January 22, 2011 Posted January 22, 2011 frogy, that's wild, I would never have imagined mold on stars, but I guess it makes sense. You've got binders like dextrin, wheat paste, rice starch, and if the rest of the star is charcoal and KNO3, plenty of nutrients. I wonder if a star with barium or strontium would support mold. I guess it would be possible even for corned BP to get moldy, due to the binder. First post! (applause) A friend of mine had the same experience - stored charcoal stars in an airtight container, and found them covered in mold several days later. They didn't explode though. Any idea how to prevent the mold? And what the heck is the mold feeding on, anyway - the dextrin?? Thanks...
Recommended Posts