I've been brewing since 2009 with my process slowly evolving to improve my beer over the years. Three or four years ago, I switched up my mashing setup. I went from stainless pot covered in blankets (since 2009) to a RIMS system. In my previous setup, I would do step mashes by adding boiling water, to hit my marks. With the RIMS, the boiling water is obviously no longer necessary. I love my RIMS system but some for some reason I'm not getting the attenuation I used to get.
Over the years, I've had a rolodex of Belgian brews that I would make---Saison (Wyeast 3724/WLP 565), Patersbier, Dubbel and Quad (Wyeast 3787/WLP 530)--in between various other brews. In the case of these Belgian ales, I would make starters for each Wyeast and WLP and pitch both. I do a step mash for all of these beers and all of them are open fermented:
SAISON STEPS (Wyeast 3724/WLP 565)
122 - 15m
131 - 15m
144 - 20m
148 - 30m
152 - 20m
163 - 30m
9% of the fermentables is candi syrup. Start ferment at 62 before slowly raising temp to 95 degrees over 7-9 days. The beer is open fermented for 3-4 of these days, cropping every 24 hours, before capping. Yeast is harvested for bottling. On the previous system, my attenuation was 94%. On the RIMS system, my attenuation is now 81%. I understand that 81% is still 81%, but I'm not sure I understand the sudden dropoff.
PATERSBIER/DUBBEL/QUAD STEPS (Wyeast 3787/WLP 530) - generally the same steps for all
122 - 15m
131 - 20m
148 - 75m
152 - 20m
163 - 30m
Candi syrup makes up 10% (patersbier), 7% (dubbel) and 16% (quad) of fermentables. Start ferment at 68 before slowly raising temp to 84 degrees over 7 days. Open ferment for 3 of these days, cropping every 24 hours, before capping. Yeast is harvested for bottling and for the next brew---I brew the patersbier to use the yeast for the dubbel or the quad. On the previous system, my attenuation was 88% (patersbier), 85% (dubbel) and 85% (quad). On the RIMS system, my attenuation is 74% (patersbier) and 78% (dubbel). I have not brewed the quad on the RIMS system yet since it's quite an investment of time.
I also make a Kolschbier and when I switched to this RIMS system, again, I'm running into lower attenuation.
KOLSCH STEPS (Wyeast 2565)
145 - 60m
158 - 30m
Closed ferment at 60. When fermentation is close to complete, slowly raise temp to 68. On the previous system, attenuation was 85%. On the RIMS system, attenuation is 75%.
I have not made any major changes to my process since switching to the RIMS. Fermentation practices are the same and my mash pH is fine. Am I destroying the enzymes? My element isn't scorched or anything. I have a good flowrate and my temps are stable. My brewhouse efficiency went up a few points but I've readjusted my equipment profile in Beersmith to offset after the first couple brews. I'm hitting my numbers going into the fermenter but the yeast is not finishing the same way.
Additional note---I rouse the yeast after each crop when when open fermenting.
Over the years, I've had a rolodex of Belgian brews that I would make---Saison (Wyeast 3724/WLP 565), Patersbier, Dubbel and Quad (Wyeast 3787/WLP 530)--in between various other brews. In the case of these Belgian ales, I would make starters for each Wyeast and WLP and pitch both. I do a step mash for all of these beers and all of them are open fermented:
SAISON STEPS (Wyeast 3724/WLP 565)
122 - 15m
131 - 15m
144 - 20m
148 - 30m
152 - 20m
163 - 30m
9% of the fermentables is candi syrup. Start ferment at 62 before slowly raising temp to 95 degrees over 7-9 days. The beer is open fermented for 3-4 of these days, cropping every 24 hours, before capping. Yeast is harvested for bottling. On the previous system, my attenuation was 94%. On the RIMS system, my attenuation is now 81%. I understand that 81% is still 81%, but I'm not sure I understand the sudden dropoff.
PATERSBIER/DUBBEL/QUAD STEPS (Wyeast 3787/WLP 530) - generally the same steps for all
122 - 15m
131 - 20m
148 - 75m
152 - 20m
163 - 30m
Candi syrup makes up 10% (patersbier), 7% (dubbel) and 16% (quad) of fermentables. Start ferment at 68 before slowly raising temp to 84 degrees over 7 days. Open ferment for 3 of these days, cropping every 24 hours, before capping. Yeast is harvested for bottling and for the next brew---I brew the patersbier to use the yeast for the dubbel or the quad. On the previous system, my attenuation was 88% (patersbier), 85% (dubbel) and 85% (quad). On the RIMS system, my attenuation is 74% (patersbier) and 78% (dubbel). I have not brewed the quad on the RIMS system yet since it's quite an investment of time.
I also make a Kolschbier and when I switched to this RIMS system, again, I'm running into lower attenuation.
KOLSCH STEPS (Wyeast 2565)
145 - 60m
158 - 30m
Closed ferment at 60. When fermentation is close to complete, slowly raise temp to 68. On the previous system, attenuation was 85%. On the RIMS system, attenuation is 75%.
I have not made any major changes to my process since switching to the RIMS. Fermentation practices are the same and my mash pH is fine. Am I destroying the enzymes? My element isn't scorched or anything. I have a good flowrate and my temps are stable. My brewhouse efficiency went up a few points but I've readjusted my equipment profile in Beersmith to offset after the first couple brews. I'm hitting my numbers going into the fermenter but the yeast is not finishing the same way.
Additional note---I rouse the yeast after each crop when when open fermenting.
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