Has anyone used Costco powdered sugar? I assumed powdered sugar was powdered sugar...wrong. This stuff made my buttercream so gritty and sweet it was not edible. I usually use Wal mart brand and it's fine. Should I go to something like Domino? Will there be a difference from the Walmart brand?

I never knew Costco sold their own brand of powdered sugar. At my Costco store they sell the Redpath icing sugar for much cheaper than any other grocery store so I buy it there. I always stick to Redpath brand.

I only saw one kind. It's a 7lb bag for $4.00. I through the whole thing away.

Yes, I have used it and had the same experience you had.  I like their bulk flour and caster sugar, but not the powdered sugar.  Since then I have noticed that whenever a question comes up about powdered sugar, the general consensus is that this is one of those items worth paying more for - quality over quantity. 

I have had the same problem with the sams club big bag of powdered sugar. I dont use it for frosting anymore

I buy Domino's powdered sugar at Sam's Club and have never had a problem!  An easy fix may be to sift it once or twice before using for buttercream though - that's what I do if mine ever gets lumpy from humidity.

I'm buying domino's from now on as well. I tried it and it's great. You can really tell the difference.

The Sam's club brand of powdered sugar is beet sugar, not cane sugar.  I never use beet sugar as I tend to have poor results.  If a PS is made with cane sugar it will say so in the ingredients (c&h, domino...) if it just says sugar, it is most likely beet.  Sugar in any form is one of the ingredients I never skimp on.

I agree with Kitty, Make sure the bag says Cane Sugar, otherwise you get gritty icing.

Hmm, I got the 7lb bag of Costco powdered sugar and didn't have any problems with it. I do live in a dry climate though so that could make a difference.

I know most powdered sugars contain corn starch to help with it not lumping.  Maybe the Costco sugar has more corn starch??

I only know about this because a friend has an allergy to corn products and I am her Trader Joe Mule.  When she needs powdered sugar I will go there to pick it up for her.  The only powdered sugar we can find without cornstarch.  And who knew tea bags were made from corn silk!?!  Found that out the hard way.