Slow cooker bourbon meat recipe bitter

I have a recipe for bourbon braised spare ribs which calls for boiling the following sauce in a pan and then pouring it over 1lb ribs (boneless or bone in) and braised in the oven for several hours.

1/2 cup teriyaki sauce
3/4 cup bourbon
1 T. honey
1 tsp. dijon mustard
1/4 cup brown sugar
3 cloves garlic
1 medium onion, sliced

So I decided to use this sauce over a 2 lb brisket in the slow cooker. I doubled the sauce recipe since I was using double the meat and wanted a lot of liquid to cover the meat. I mixed the sauce in a bowl and poured it into the slow cooker over the meat (without pre-boiling the sauce). I cooked for 10 hours on low and the meat was soft and juicy and just right. However, there was quite a bitter taste, which I'm assuming is from the whiskey. Is it because I doubled the recipe? Or because the whiskey had to first be boiled and then cooked on low?

Best Answer

Doubling the recipe should work fine. I think the most likely reason is that you didn't end up boiling off the alcohol. Alcohol boils around 173F, and a slow cooker on low heats to between 170 and 280, so on the lower end that's too cool. I assume the pot was also covered the whole time, so that even if you did boil off the alcohol, some could have dripped back into the sauce.