Just thought I'd share an interesting tip that I've had to suss out myself. I have been making cupcakes for a couple of years now and the vanilla recipe I use I had perfected right down to the specific oven temperature to get the nice dome I wanted.

Anyway long story short, I found a different brand of baking powder that was MUCH cheaper so bought it (in bulk too) and my cupcakes were coming out weird. They were rising fine then all of a sudden it was like a volcano, so they came out of the oven with a massive burst volcano top and then would sink massively round the sides.

Longer story even longer - not all baking powders are created equal. I had to reduce my oven temperature by 50 degrees!!!!! The baking powder might be cheap, but now I have had to add an extra ten minutes onto the baking time which all adds up at the end of the day.

Oh well, lesson learned.

Well, I know there's single acting and double acting baking powder. explanation from wikipedea...

The acid in a baking powder can be either fast-acting or slow-acting.[6] A fast-acting acid reacts in a wet mixture with baking soda at room temperature, and a slow-acting acid will not react until heated in an oven. Baking powders that contain both fast- and slow-acting acids are double acting; those that contain only one acid are single acting. By providing a second rise in the oven, double-acting baking powders increase the reliability of baked goods by rendering the time elapsed between mixing and baking less critical, and this is the type most widely available to consumers today. Double-acting baking powders work in two phases; once when cold, and once when hot

You're right!! After one bad batch, I no longer trust generic baking powder. And I only buy it in the small cans...it's more expensive, and I seem to be opening a new one every week, but at least it's dependable.

It's not only baking powder... one holiday a couple of years back, my sister and I were testing some cookies to be given out to clients. We had the GM flour brand, and then when real baking time came, we bought a big sack of flour from Costco and got different results on the cookies we tested. We realized it was the flour, as it was the only one different from our testing ingredients...and had to buy Gm flour for better looking cookies! I would never change my brand of flour now except for King Arthur.