I visited our local Mennonite bulk sale store & bought a product called Therm-Flo. They also had Clear Jel available but the sales person told me that the Therm-Flo was what they used in canning. The package does say canning & freezing.
BUT when I looked on the gov. site, Clear Jel is the only one mentioned. Is anyone familiar with this? There's so much said about thickening products like flour, etc. being dangerous to can with--I don't want to make a fatal mistake.
They are both somewhat the same thing, modified and reprocessed corn starch. Clear Jel is the brand used in all the USDA testing and the recipe measurements specify the Clear Jel as you mentioned.
Apparently, from the information available, because the Clear Jel is slightly more acidic and somewhat more refined and so less inclined to break down during processing. IF that is true then they may not exchange 1 for 1 when measuring them. I can't say for sure. But otherwise I know of no reason why they can't be used interchangeably. It is your choice whether to use the one recommended by the guidelines or this other product.
One thing I do know from personal experience and from reports by others, unless you like VERY thick, almost jelled, pie fillings use less than is called for in the instructions. Some have reported using as much as 1/2 less.
I ended up buying a whole bag of ClearJel because it was not available any other way locally. I too, would like to know the answer to this question. I would think that sealing the powder would ensure a much longer "shelf life".
I did not want the expensive that clear jel would add to the cost of making pie fillings. I simply chose to make the pie fillings and leave out any thickener.
I opened a jar of apple pie filling yesterday and stirred in some cornstarch before I added the filling to the pie shell. The pie turned out great. You can always add the thickener of your choice before baking.