I have a bit of a head scratcher. At the end of August, I brewed a Brown Ale (OG 1.050) that was supposed to ferment to 1.011, but it stalled at 1.030. I fermented at 68F with Lallemand London English Ale. I attributed the stall to one or both of the dumb mistakes I made when brewing:
First, I forgot to turn off the heating element when I mashed in (152F mash temp) and it got to strike temp (162F) before I was able to get the temp back down... took about 10-15 min. to get back down to 152F. Boneheaded mistake, but I didn't expect it to have a major impact.
Second, I spund my beers. So after a couple days, I opened the ferm chamber to check gravity using a tilt (I need to get right next to the fermenter to get a reading). It was at 1.030, so I didn't apply the spunding valve at that point, but in the process, I must have knocked the temp probe off the side of the fermenter and it hung outside the chamber when I closed it. I use a mini-fridge as a chamber, so with the probe at ambient, I essentially cold-crashed my beer at 1.030. After another day or two, I realized what happened and my beer was at 35F. RDWHAHB, right? So I let it get back to fermentation temp however, it never moved off of 1.030. I raised the temp to 75F and still nothing.
I gave the fermenter a shake (I use 6.1 gallon torpedo kegs to ferment, so no concerns of introducing O2) to rouse the yeast... Nothing.
I took a sample to check the gravity using a hydrometer in the event the tilt was malfunctioning.. It too read 1.030.
In a last ditch effort to solve it, I used the beer to make a starter and added it back to the beer. Nothing.
At that point, I assumed the beer had reached a high FG due to the high initial mash temp. I had no interest in drinking the beer at 1.030, so I intended to dump it as a sacrifice to the beer gods for my mistakes, but set it aside in the mean time.
A week ago when checking the gravity of another beer, my tilt app got a read on the Brown Ale and it read 1.029. I didn't think anything of it as it can fluctuate slightly, but figured I'd keep an eye on it. A few days later, it read 1.027. I checked again today... 1.023.
I don't know if it was already "stalled" at 1.030 when I accidently cold crashed it or if it was actively fermenting, causing it to stall at 1.030.
Regardless, I'm confused now. Could the high mash temp have made some of the sugar more difficult to ferment resulting in the slow drop from 1.030 to 1.023?
Could I have picked up an infection when adding back the starter I made and bacteria is able to ferment what the yeast couldn't?
First, I forgot to turn off the heating element when I mashed in (152F mash temp) and it got to strike temp (162F) before I was able to get the temp back down... took about 10-15 min. to get back down to 152F. Boneheaded mistake, but I didn't expect it to have a major impact.
Second, I spund my beers. So after a couple days, I opened the ferm chamber to check gravity using a tilt (I need to get right next to the fermenter to get a reading). It was at 1.030, so I didn't apply the spunding valve at that point, but in the process, I must have knocked the temp probe off the side of the fermenter and it hung outside the chamber when I closed it. I use a mini-fridge as a chamber, so with the probe at ambient, I essentially cold-crashed my beer at 1.030. After another day or two, I realized what happened and my beer was at 35F. RDWHAHB, right? So I let it get back to fermentation temp however, it never moved off of 1.030. I raised the temp to 75F and still nothing.
I gave the fermenter a shake (I use 6.1 gallon torpedo kegs to ferment, so no concerns of introducing O2) to rouse the yeast... Nothing.
I took a sample to check the gravity using a hydrometer in the event the tilt was malfunctioning.. It too read 1.030.
In a last ditch effort to solve it, I used the beer to make a starter and added it back to the beer. Nothing.
At that point, I assumed the beer had reached a high FG due to the high initial mash temp. I had no interest in drinking the beer at 1.030, so I intended to dump it as a sacrifice to the beer gods for my mistakes, but set it aside in the mean time.
A week ago when checking the gravity of another beer, my tilt app got a read on the Brown Ale and it read 1.029. I didn't think anything of it as it can fluctuate slightly, but figured I'd keep an eye on it. A few days later, it read 1.027. I checked again today... 1.023.
I don't know if it was already "stalled" at 1.030 when I accidently cold crashed it or if it was actively fermenting, causing it to stall at 1.030.
Regardless, I'm confused now. Could the high mash temp have made some of the sugar more difficult to ferment resulting in the slow drop from 1.030 to 1.023?
Could I have picked up an infection when adding back the starter I made and bacteria is able to ferment what the yeast couldn't?
Last edited:
