Sour-ness Disappeared: Why? How?

This makes me think of acetaldehyde, which can make a beer seem cidery but can be consumed by yeast. But I feel like we already suggeste and dismissed this idea in an earlier thread about this beer? On the other hand, you only say you found one beer that isn't sour, so it may be early to jump to conclusions.

 

In that case, I'm going with acetaldehyde as the new hypothesis. However, you are the first person I know to complain about heartburn that is (hypothetically) related to acetaldehyde. Acetaldehyde can be a consequence of bottling too soon, before the yeast have had a chance to clean up after themselves. Eventually, whatever yeast that get transferred to secondary fermenters or bottles can take care of it, but ideally, you let them take care of things before transferring. One caveat - there are bacteria that will produce this compound too, so if you have a persistent problem, with cidery-ness increasing with time, it could mean infection. But with 10 or so good beers, you might be in the clear. Pat yourself on the back and enjoy your homebrew!

 

I'm not sure what causes it, but I have had fairly bad heartburn from some beers as well. The reason I'm chiming in on this is because a recent beer that I made (an IPA) had an apple flavor to it that I would describe as "cidery." The beer is still on tap, and I had some over the weekend. The cidery flavors have fallen out a lot, and now it tastes like a good (very bitter) IPA. At first I just thought the cidery flavors were from the bittering hops (Admiral), but what has been described here is indicative of my batch as well. (Note: this was the first and only time I have used Admiral hops)
This batch did ferment a bit higher than normal (low 70's), which I assume would contribute to high acetaldehyde levels.
Anyway, I will likely do a bit of research about heartburn from beer, because I'm growing more curious as I write this, so you will probably see a new thread about it soon.