I've been brewing jalapeño beers for a while now and believe I have settled on using 8 in my 5.25 gal batches for a great flavor/aroma aspect with enough spice to know its a pepper without being overly spicy that you may not want to drink many, and I love fresh peppers.
With that in mind, and liking very spicy dishes (I eat serranos and Thai chili saw well), I decided I wanted to make a burn your throat strong ale using Habaneros. Having never worked with these I figured 4 might be plenty as the scoville units are off the charts compared to jalapeños. As it turned out upon my sample at bottling it's not even remotely spicy.
I roasted 2 in the oven at 350* for 30 mins and sliced thin. These were saved for brew day and went into the boil at 14 mins. The other two were left raw, sliced thin, and placed in vodka for a few weeks and added to the bottling bucket. This is my routine for my jalapeño beers.
So how many peppers does one need to get the heat noticeable?