Accidentally boiled my partial mash grains...

[MizooBrew]

Yup. I screwed up. I had been mashing my grains at ~152 for 30some minutes when I noticed my temp had dropped to ~145. So I increased my heat and, unfortunately, I let myself get distracted and the grains boiled for about a minute or so. I then dropped the grains back down to ~150 and continued the mash for a bit, although I figured I had denatured the enzymes necessary for starch conversion. Anyhow, this Irish Red Ale has now been in primary for one month and is finished fermenting. I pitched an appropriate starter (OG 1.060), but my brew appears to have finished at 1.020.
My theory? Boiling the grains extracting lots of proteins that are now keeping my gravity high despite how much sugar is reduced. I had 18oz of grains for my partial mash (1.125lb), and 8.1lb of LME. Could cold crashing cause these proteins to precipitate out and still leave me with enough yeast to naturally carbonate? If not, is there any other solutions? Do finings help reduce protein levels? Does my speculation that proteins are the culprit seem plausible?

 

[jester5120]

boiling the grains shouldn't be the culprit. if you've ever looked at a technique called decoction mashing the grains actually get brought up to a boil. malt extract in general doesn't ferment out very dry there are usually some residual sugars left. Irish reds aren't super dry either 1.014 is a reasonable fg. so you're not too far off. make sure your hydrometer is calibrated and that you're accounting for any temp difference (hydrometers are accurate at 60* so if your wort is 70 you need to account for that). try racking into a secondary fermenter to help drop more stuff out, if you haven't already, before you cold crash. cold crashing will still allow you to bottle condition but it'll take a lot longer.

 

[wyzazz]

Your beer is most likely done because you denatured the enzymes too early while mashing, you can try to warm it up a bit and rouse the yeast to see if it gets down any further. At 1.020 your beer may also just be finished, it's not a bad FG for PM or Extract brewing. Taste it, is it sickeningly sweet?

As far as cold crashing goes, I have cold crashed almost all of my bottled beers with no ill affects. It may take a few extra days to carb up but the clarity is worth it IMHO.

 

[MizooBrew]

Your beer is most likely done because you denatured the enzymes too early while mashing, you can try to warm it up a bit and rouse the yeast to see if it gets down any further. At 1.020 your beer may also just be finished, it's not a bad FG for PM or Extract brewing. Taste it, is it sickeningly sweet?

As far as cold crashing goes, I have cold crashed almost all of my bottled beers with no ill affects. It may take a few extra days to carb up but the clarity is worth it IMHO.

The beer is not sickenly sweet, it actually seems reasonably dry for how high the gravity is. That is what I speculated that something besides residual sugars were keeping the gravity high. I will try rousing the yeast a bit, see what I can get. I will definitely start cold crashing after that as well, I was never completely sure if it was alright to cold-crash ales until now.

 

[bja]

Your beer is most likely done because you denatured the enzymes too early while mashing,

Sounds to me like he was steeping the grain, no mashing. WTH mashes 18 oz of grain?

 

[wyzazz]

Sounds to me like he was steeping the grain, no mashing. WTH mashes 18 oz of grain?

He said Partial Mash so I ran with it, hopefully the OP will chime in as to whether he had any base malt in that steep/mash or not.