I'm new to this board, and am thrilled with all the great advice people give. I recently visited a wonderful bakery. I've probably tried 20 recipes over the last couple weeks to try to make a similar dense, rich cupcake. I'm getting closer, but not quite there. While searching the internet for cupcake recipes, I think I found the bakery's frosting recipe. It has butter and half and half. I usually use butter in my normal buttercream and keep it at room temp. I'm wondering about the half and half though. It was very rich and cream. This bakery doesn't refrigerate it. Would the sugar act as a preservative so it could stay at room temp? Thanks for your expertise!

Hi and Welcome to CC, supermom419.

American buttercreams are shelf stable because they use very large amounts of powdered sugar and fat with small amounts of liquid. The powdered sugar, which is hygroscopic, controls the water activity in the small amount of liquid (be it water, milk, cream or 1/2 & 1/2).

Water activity & microbial growth:
(Prolonging Bakery Product Life.)

http://tinyurl.com/ya8po4z

WJ Scott in 1953 first established that it was water activity, not water content that correlated with bacterial growth:

http://tinyurl.com/bmsato

Formulating for increased shelf life:
(Decreasing water activity results in hostile environment for bacteria.)

http://tinyurl.com/csu2b9

HTH

Thanks JanH for your response!

You're welcome supermom419.