I have my doubts about the bolded section. Beer does have “alpha acids” from the hops, but we’re talking parts per million, and as far as I know tannins in beer are considered a flaw in the vast majority of styles. (Former professional brewer and brewing chemist)
I’m not doubting that beer might work better, but isolating alpha acids and tannins as the cause is sketchy at best.
Pork loin is a big long thing. Pork tenderloin is a long skinny thing. Pork sirloin roast is a fatter, rounder thing (possibly a cut-down piece of the big long thing). 
Believe what you want. In my experience (and I routinely cook with beer, wine, broth, cider [awesome for pork], water–all of them), this is just cooking myth and folklore. I’ve even given you a cite that says as much. But, whatever. Anyone out there, feel free to experiment for yourselves and come to your own conclusion.
And I gave you 2 cites. I can give you more. I don’t know what is in it or how it works. I don’t know if it’s universal among beers. I use a cheap beer and it’s profoundly noticeable.
Yes, you’ve made that clear. And I’ve stated I’ve noticed no difference, with my own cite. Let’s leave it at that. Anyone interested can do their own experiments and come to their own conclusions.
All went well. When I got home at 5:30, my plan was to remove the potatoes and carrots, but they were still firm! Maybe due to the size of the roast (it was large)? Turns out I needed more cooking time.
Anyway, I added a bottle of Magic Hat HiPA, and let it cook. Around 7:45 I poked the meat around a bit and it broke up nicely.
I peeled, cored, and chopped some apples and made applesauce as a side. There were compliments for the chef!
Ta da! Glad you actually checked. I had my suspicions that 8 hours on low may not quite do it, depending on the size of the roast.
Did you put the veggies down on the bottom under the meat? The low setting doesn’t provide enough heat to tenderize potatoes and carrots as quickly as meat.
The pot was layered. some sauerkraut, then a few vegs, then meat with more vegies alongside and on top, them more kraut over all. Yumm!
The low on my crockpot would have dissolved all the vegetables in 8 hrs. The last time I did this I had to go out and buy more veggies to toss in.
I’ve had a few different slow cookers in my life and it is interesting how widely the temperatures for the settings vary. My last one was like you described. Even on low, I couldn’t put veggie in in the morning. I never used the high setting. My current one, the low is much lower and it works for veggies all day. High is great if I have less time.
Interesting. I’ll have to check the temp next time I use it. I love the locking lid design but it’s old school.
You made pork, kraut, and beer for your girlfriend?
What a great gal!
:D:cool: