My husband and I took a look at Costco yesterday to see if we could lower my ingredients bills. We noticed that their powdered sugar has cornstarch in it. How or will this have any effect on my frosting, fondant, etc.?
I use Costco's powdered sugar all the time and have never noticed a difference; however, I am not a professional. I believe all powdered sugars have cornstarch in them.
99% of powdered sugar has cornstarch to prevent caking. Use like normal, you have probably had it all along.
The costco sugar has beet sugar in it instead of being pure cane sugar. From what I understand from my instructor you don't want to use beet sugar in a BC brcause it doesn't hold up as well as cane sugar. I forgot what she said precisely would/wouldn't happen if you use beet sugar. I just stored it and moved on. lol!
My Wilton instructor told us that powdered sugars actually vary in their cornstarch content based on the areas to which they are shipped - so the stores in our humid South Texas climate, for instance, would receive sugar with more cornstarch in it than, say, the stores in Arizona.
I would love to be able to verify that!
The difference between cane sugar and beet sugar, as far as I can tell, is that cane sugars will give a smoother, creamier icing. Beet sugars are a little more gritty.
I don't know what costco sells, I know Sam's club used to sell a 50 lb beet sugar bag and a 20 lb (i think) cane sugar bag.
But the original question about corn starch. Corn starch is added to all the powder sugar I have ever seen. It's to prevent caking. It's what helps the sugar stay in a fine powder and not react to humidity.
I'm not a pro either - but I use costco powder sugar all the time - I am on my 3rd 50# bag. The only thing that I don't like about it is that after you open the bag you always have to sift the sugar before you use it or its lumpy.
if you buy the 2# bags from wal-mart - you just open and dump - I really HATE sifting!!
It is much cheaper and I never noticed a difference in my buttercream/fondant or anything.