So a few weeks ago I brewed my ESB recipe. It's a pretty straightforward recipe and I have brewed it multiple times without issue. Anyway, I got distracted, overly confident, and ahead of myself and without even thinking ended up doughing the grain into the (preheating) mashtun waaay too early. The water was probably around 190 - 200 degrees which put the mash around 175. By the time I was able to ice it down to the 156 I was shooting for about 30 minutes had passed. I figured the damage was already done, but continued with the brew as usual.... Mostly out of curiosity to see what I would end up with. My rig usually pulls consistent 75-76% efficiency, this only got about 62%. OG 1.054. I was fully expecting astringent off tastes, but other than that had no idea how this would turn out.
Here is where I am confused. My understanding is that by mashing this high I would have extracted more unfermentable sugars, which would produce a very full bodied beer. Because of the high mash, I was expecting a final gravity around 1.02x. FG hit 1.008 which is lower than normal for this recipe. Why would it end lower if there are less fermentable sugars?
I tapped it yesterday. It's not as awful as I thought it would be. Very full bodied, but not sweet at all. The overwhelming off-flavor is a very metallic aftertaste. Like chewing on a penny metallic, that doesn’t come until a few seconds after tasting. The astringency I was expecting is there, but not overwhelming. From what I have researched the metallic taste is almost always attributed to water... Not mash temperature. Like I said, I have brewed this exact recipe multiple times with the same water setup so I'm pretty confident that my water is not the issue. The only explanation I can think of is that the high mash temperature adjusted the PH of the mash which may have caused the metallic taste? Can anyone chime in on this?
I (thankfully) have never really had off flavors before so this is a whole new world to me. Just trying to use my mistake as a learning experience.
This might have to be my first 10 gallons down the drain...