Brewed a Kolsch two weeks ago. It's an all grain recipe that I've made before but with a new mashing method and on a new system.
When I've brewed this in the past, I mashed in at 148 for 60 minutes and lost a couple degrees over the course of an hour finishing at 146 (at the time, didn't have heat control over my mash tun). And did not mash out. Fermented at 66 (didn't have temp control and know this is high for the style). Reached terminal gravity 7 days at 1.010. Verified this several days later.
This go-around, I attempted to mash using the Hochkurz method. Mashed at 145 for 60 minutes and then 158 for 30 minutes. And I mashed out at 168 for 10 minutes. This was on an electric RIMS system so temp was constant. Now I have temp control for fermentation and set the fermenter to 60 but pitched yeast at 65 degrees. During fermentation, the internal temp reached 63 a day or two in, then made its way back down to 60. Then on day 8, I let the temp free rise to 65 over a couple days and it's been there for the last five days until this morning where it's dropping on its own---currently at 64. The current gravity is 1.014 after two weeks.
My OG in both cases was 1.056 (a bit high for the style).
The current batch has an attenuation of 74% whereas before, I got 81%.
I have an iSpindel in my fermenter so I can monitor what's going on and the gravity hasn't changed since day 10. And to be clear, the gravity numbers I'm giving you are from pulled samples with a traditional hydrometer. The fact the the beer is starting to drop in temp after free rising suggests to me that it's done. If this is the case, I'm a bit surprised my attenuation being 7 points lower. I made a proper starter on a stirplate that fermented out and was chilled and decanted, etc. The yeast packet was brand new according to the date on the package.
I will say the gravity sample that I tried yesterday did have some traces of diacytel and still had some bubbles in it. I left the sample alone for a couple hours while it degassed until it was still to verify the reading was accurate. With the activity, I'm sure the yeast still needs to clean up, but would that also mean I'll drop 4-5 points at this stage? My gut says probably not.
Was 145 too low? Did I not give it enough time at 145? Or is the lower fermentation temp a reason for the yeast to move slowly and this beer isn't done yet?
I've attached an image of the fermentation chart---plato/temperature. while the plato numbers on the chart would suggest I hit the accurate numbers, I should mention my iSpindel is not accurate (the weight is off) and, again, the numbers I measured are from my traditional hydrometer. Temp is green, plato is blue.
When I've brewed this in the past, I mashed in at 148 for 60 minutes and lost a couple degrees over the course of an hour finishing at 146 (at the time, didn't have heat control over my mash tun). And did not mash out. Fermented at 66 (didn't have temp control and know this is high for the style). Reached terminal gravity 7 days at 1.010. Verified this several days later.
This go-around, I attempted to mash using the Hochkurz method. Mashed at 145 for 60 minutes and then 158 for 30 minutes. And I mashed out at 168 for 10 minutes. This was on an electric RIMS system so temp was constant. Now I have temp control for fermentation and set the fermenter to 60 but pitched yeast at 65 degrees. During fermentation, the internal temp reached 63 a day or two in, then made its way back down to 60. Then on day 8, I let the temp free rise to 65 over a couple days and it's been there for the last five days until this morning where it's dropping on its own---currently at 64. The current gravity is 1.014 after two weeks.
My OG in both cases was 1.056 (a bit high for the style).
The current batch has an attenuation of 74% whereas before, I got 81%.
I have an iSpindel in my fermenter so I can monitor what's going on and the gravity hasn't changed since day 10. And to be clear, the gravity numbers I'm giving you are from pulled samples with a traditional hydrometer. The fact the the beer is starting to drop in temp after free rising suggests to me that it's done. If this is the case, I'm a bit surprised my attenuation being 7 points lower. I made a proper starter on a stirplate that fermented out and was chilled and decanted, etc. The yeast packet was brand new according to the date on the package.
I will say the gravity sample that I tried yesterday did have some traces of diacytel and still had some bubbles in it. I left the sample alone for a couple hours while it degassed until it was still to verify the reading was accurate. With the activity, I'm sure the yeast still needs to clean up, but would that also mean I'll drop 4-5 points at this stage? My gut says probably not.
Was 145 too low? Did I not give it enough time at 145? Or is the lower fermentation temp a reason for the yeast to move slowly and this beer isn't done yet?
I've attached an image of the fermentation chart---plato/temperature. while the plato numbers on the chart would suggest I hit the accurate numbers, I should mention my iSpindel is not accurate (the weight is off) and, again, the numbers I measured are from my traditional hydrometer. Temp is green, plato is blue.