I have been brewing for a while and overall happy with how my beer is coming out but seem to regularly end up with higher than desired final gravity levels.
It seems to be almost all of my beers but I will use this Hop Head Kit as an example.
My first thought is that I am under pitching my yeast. I make a 2L starter in a temp controlled stir plate and let it go for about two days at the recommended temp for that yeast. I used WLP005 British Ale Yeast for the Hop Head and kept it at 66F. I then turn off the stir plate, remove the stir bar, and drop the temp down to 38F for about six hours. After all of the yeast has settled to the bottom I decant all but a little bit of the wort stir it back up and let it warm up to around 70F before pitching it. Seemed to be a sizable amount of yeast.
My second thought is my mash temp is too high. I have a single induction burner with two pumps and three 10 gallon kettles. I have a built-in copper coil in my brew kettle and start by heating 9.5 gallons of strike water to 160F. I added two extra pounds of two row and .6 pounds of acid malt for a total grain bill of 18.1 pounds. I pump 5.8 gallons of the strike water through the coil to my mash tun and then set up one pump recalculating the wort through the coil in my brew kettle and the other pump is whirl pooling the water in brew kettle. Basically, my brew kettle is my hot liquor tank until I sparge. After I add my grains and stirred them in well I turn on the pumps and the burner. My mash starts out around 120F and I bring it up to 152F and am careful not to go over. I have good thermometers in my kettles have checked them with a temp probe.
Here is where I may be causing problems. In order to bring my mash temps up faster, I have been overshooting my hot liquor tank temps and then turning off my burner and letting them settle at my target. For example, my mash started out at 120F and I want it at 152F. I will bring my HLT up to about 177F and then turn of the burner. The MT will climb up to 152F and the HLT will drop to 154F and then I turn the burner on low to keep at that temp for about an hour. If it looks like I may go over the 152F in the MT then I can pull the lid off of the HLT and if the temps are still going up I can turn the wort pump off until the temps come down. Even thought my MT thermometer never went over 152F I am wondering if the wort temp coming out of the HLT coil is much hotter and causing my attenuation problems?
After the hour I bring the water in my BK/HLT up to 180F and the temp in my MT to 168F. I then pump my sparge water thought the coil in the BK into my HLT. From there its pumped to the MT with an auto-sparge and the wort is pumped to the BK and I start to boil. I believe the 180F sparge water is hitting the mash at about 172F.
I am typically getting about 88% efficiency with smaller grain bills. With this larger grain bill I hit a 1.095 gravity at 5.5 gallons for a 79.2% efficiency. My target final gravity is 1.025 for an abv of 9.2. I cooled the wort to 66F and aerated well with a wine degassing stir on a drill. I keep the temp in the fermenter at 66F for the first week and then upped it to 68F for a second week. I then pitched dry champaign yeast and brought the temps up to 70F and held it there for two more weeks. After the month in the primary my gravity is still at 1.036. I just racked it on the hops and will then cold crash it and keg in two weeks. There was still some airlock activity before I racked it but the gravity readings were not falling very much.
Here is my fermenter temps setup:Glycol Temp Control Set Up
Thanks in advance for any suggestions.
It seems to be almost all of my beers but I will use this Hop Head Kit as an example.
My first thought is that I am under pitching my yeast. I make a 2L starter in a temp controlled stir plate and let it go for about two days at the recommended temp for that yeast. I used WLP005 British Ale Yeast for the Hop Head and kept it at 66F. I then turn off the stir plate, remove the stir bar, and drop the temp down to 38F for about six hours. After all of the yeast has settled to the bottom I decant all but a little bit of the wort stir it back up and let it warm up to around 70F before pitching it. Seemed to be a sizable amount of yeast.
My second thought is my mash temp is too high. I have a single induction burner with two pumps and three 10 gallon kettles. I have a built-in copper coil in my brew kettle and start by heating 9.5 gallons of strike water to 160F. I added two extra pounds of two row and .6 pounds of acid malt for a total grain bill of 18.1 pounds. I pump 5.8 gallons of the strike water through the coil to my mash tun and then set up one pump recalculating the wort through the coil in my brew kettle and the other pump is whirl pooling the water in brew kettle. Basically, my brew kettle is my hot liquor tank until I sparge. After I add my grains and stirred them in well I turn on the pumps and the burner. My mash starts out around 120F and I bring it up to 152F and am careful not to go over. I have good thermometers in my kettles have checked them with a temp probe.
Here is where I may be causing problems. In order to bring my mash temps up faster, I have been overshooting my hot liquor tank temps and then turning off my burner and letting them settle at my target. For example, my mash started out at 120F and I want it at 152F. I will bring my HLT up to about 177F and then turn of the burner. The MT will climb up to 152F and the HLT will drop to 154F and then I turn the burner on low to keep at that temp for about an hour. If it looks like I may go over the 152F in the MT then I can pull the lid off of the HLT and if the temps are still going up I can turn the wort pump off until the temps come down. Even thought my MT thermometer never went over 152F I am wondering if the wort temp coming out of the HLT coil is much hotter and causing my attenuation problems?
After the hour I bring the water in my BK/HLT up to 180F and the temp in my MT to 168F. I then pump my sparge water thought the coil in the BK into my HLT. From there its pumped to the MT with an auto-sparge and the wort is pumped to the BK and I start to boil. I believe the 180F sparge water is hitting the mash at about 172F.
I am typically getting about 88% efficiency with smaller grain bills. With this larger grain bill I hit a 1.095 gravity at 5.5 gallons for a 79.2% efficiency. My target final gravity is 1.025 for an abv of 9.2. I cooled the wort to 66F and aerated well with a wine degassing stir on a drill. I keep the temp in the fermenter at 66F for the first week and then upped it to 68F for a second week. I then pitched dry champaign yeast and brought the temps up to 70F and held it there for two more weeks. After the month in the primary my gravity is still at 1.036. I just racked it on the hops and will then cold crash it and keg in two weeks. There was still some airlock activity before I racked it but the gravity readings were not falling very much.
Here is my fermenter temps setup:Glycol Temp Control Set Up
Thanks in advance for any suggestions.