Hi all
I thought I'd share my story of mashing fails that I thought for a month or more was actually stuck ferments. It wasn't, I've learned a valuable lesson, and I'd like to share it.
Long story short; by not correctly controlling my mash temp I was leaving too many unfermentable sugars it would seem.
I'm a new brewer starting in August '15 and here's what I encountered recently:
Batch #009 - German Pils (Brewing Classic Styles): my OG 1044, target FG: 1009, my FG: 1019
Batch #010 - Sierra Nevada Pale Ale clone ('Nierra Sevada' from HBT forum): my OG 1040, target FG: 1012, my FG: 1018
Batch #011 - Brewdog 5am Saint clone (Brewtoad Recipe database): OG 1044, target FG: 1012, my FG: 1020
Batch #012 - Janets Brown Ale (Brewing Classic Styles): OG 1064, target FG: 1017, my FG: 1026
In each of the above cases I couldn't get the FG to move short of extreme measures; I roused & warmed, pitched more yeast via starter, I tried some brewers yeast from a local craft brewer, I even tried Champagne yeast vs Janets Brown but none of these methods would shift my FGs across these batches.
I despaired and despaired and each hydrometer reading on 'stuck' batches was like a kick in the guts.
For batch 10/11 I eventually blitzed the bastards with Low carb sachet (dextrose glucoamylase enzyme) and smashed their FG down to 1008 for #10 and 1003 for #11 but to the real detriment of each beer.
Eventually I was speaking to my LHBS and the guy immediately said "Oh you Biab, well that'll be your problem."
Me: "....."
<thinking to myself double facepalm this guy is an idiot>
Eventually I steeled myself to pursue this line of conversation and he explained that people with stove/ gas fired BiaB in his experience tend to have fluctuating mash temps and he bet I was mashing too high, denaturing my Beta Enzymes and thus leaving too many unfermentable sugars; thus my beers weren't actually stuck, they were just finished fermenting the sugars my mash had produced. He suggested mashing in an Esky will give greater temp control (3V) or if I wanted to stick with Biab I could try to mash a couple of degrees lower to give myself some buffer and avoid going too high.
Now my commitment to Biab is 100% and I've no intention of going to 3V/ HERMS/ RIMS/ etc so naturally I looked to the Biabbrewer.info community for answers
Simple practises like always stirring vigoursly up/down when firing the kettle and waiting to check your temp wasn't drifting up before dough-in came to light. I didn't have to just drop a few degrees to be safe I still should be able to mash at the right temp but now I had better procedures to ensure my entire body of water was the right temp before dough-in.
So that's what I did for batch #14 another crack at the SNPA clone and batch #15 a rebrew of the NRB all Amarillo Biabrewer.info recipe that I've tweaked a lot, and I'm pleased to report that for at least #14 so far no sign of a high FG. I am bloody sure I didn't go over 69c in either batch and am therefore hopeful I didn't hurt my Betas too much and thus my wort will be more what the recipe calls for.
I hope this story can provide a chuckle for anyone who's mashed too hot and a lesson for anyone who hasn't cottoned onto the importance of mash temp or is facing "stuck fermentation issues"
Lastly on a side note I was inspired by a Brulosophy article (link below) that led me to think the taste difference for a much higher FG may not be death for a beer, so for Batch #12 I just bottled J'anet Browns' with the crappy ADF% and see how it goes. I opened the first tonight and it was delicious!
http://brulosophy.com/2015/10/12/the-ma ... t-results/
cheers
Nick
"Stuck" Fermentation hell? No. Just mash temps
Post #1 made 8 years ago
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