mccabedoug
Well-Known Member
I've been making beer since Jan 2004 - 10 years next month. I've been an AG brewer since 2007 and have made probably more than 100 AG batches. I batch sparge my 5 gal batches using a 48 qt cooler containing a toilet braid. Works like a charm. For the first time ever, I have two batches in a row, made 2 weeks apart, with around 55% efficiency (down from +75%). I cannot figure this out. Here's a little background.
Crush - Each batch was a totally different grain bill (one a Yuengling clone - mostly 2 row; one a hefe which is 65% wheat/35% pils) and from two different LHBSs. So, each batch was purchased and crushed from a different home brew shop. Now, I suppose that both shops could suggenly have 'bad' crushes at the same time but that is highly unlikely. These are the two places I always buy my grains from. Both have always served me well.
Grain weight - each was weighed by me before brewing and both were exactly 11 lb of grain.
Water volumes - I batch sparge and use two 3.75 gallon volume additions using a pre-measured enamel stainless steel pot that I have been using for 10 yrs. This is around a 1.4 qt/lb mash. Not that it matters, but I sparge with around 180oF water. In the past, I've done cool water sparges and I get the same (previously good) efficiencies. Also, there is no residual liquid left in the cooler after batch sparging - the liquid has complete drained. To confirm, after the boil, I end up with around 5.25 - 5.5 gallons in the fermentor and around a quart of material leftover in the whirlpool. This never varies and did not for these two batches.
SG reading error - I cool directly from the kettle through a 30 plate chiller right into the bucket. Although unneccesary, I give the cooled wort a stir when hydrometer goes into bucket so I am quite certain that it is not a lack of wort mixing error. Also, for the hefe I made yesterday, I placed 2 hydrometers into the wort (hoping one suddenly went bad) and both came back the same: 1.044 (where my other 90+ batches read 1.054 - 1.058 for 11 lb grain bills). So, that rules out mixing & hydrometer errors.
Temperature - This is what I thought my problem was a couple weeks ago. So, I borrowed a certified glass thermometer from work (I work in a scientific equipment company and we have lots of labs) and calibrated all my thermometers using 150oF water (as measured by glass thermometer). I found out that my 'trusted' thermometer was 10 degrees low. That made me happy to find that. I also found that one of my other digital thermometers was spot on. So, for this batch, using my calibrated thermometers, I thought my temporary low eff batch was a one off due to low temps and was now in my rear-view mirror. Nope, that wasn't it. Got the same results and I know that my 152oF mash WAS a 152oF mash (as measured in different locations in the thoroughly mash using two calibrated thermometers). For fun, I measured the temp of the boiling wort and the calibrated thermometer read exactly 212oF.
Mash time - I mash for 90 minutes. Always have. I maintain a 90 min mash with NO loss in temps, even in the winter (I cover the cooler with my super-insulated ice fishing jacket). Also, my recently calibrated go-to thermometer is a turkey fryer thermometer. I drilled a small hole in the lid of my cooler a long time ago and insert this long thermometer through the lid and into the mash. I've done this since 2007 and I am confident that this reflects accurate temps.
So, I am at a loss why suddenly, with no changes at all to my brewing ingredients, process, or measurements, I have suddenly lost this much efficiency. I am an analytical chemist by training and as such I fancy myself a decent troubleshooter (I did tech support for 7 yrs) and I understand how to use design of experiments (DoE) to track down cause & effect. Also, I've been reproducibly making beer for some time so I kinda know what I am doing.
What have I missed?
Crush - Each batch was a totally different grain bill (one a Yuengling clone - mostly 2 row; one a hefe which is 65% wheat/35% pils) and from two different LHBSs. So, each batch was purchased and crushed from a different home brew shop. Now, I suppose that both shops could suggenly have 'bad' crushes at the same time but that is highly unlikely. These are the two places I always buy my grains from. Both have always served me well.
Grain weight - each was weighed by me before brewing and both were exactly 11 lb of grain.
Water volumes - I batch sparge and use two 3.75 gallon volume additions using a pre-measured enamel stainless steel pot that I have been using for 10 yrs. This is around a 1.4 qt/lb mash. Not that it matters, but I sparge with around 180oF water. In the past, I've done cool water sparges and I get the same (previously good) efficiencies. Also, there is no residual liquid left in the cooler after batch sparging - the liquid has complete drained. To confirm, after the boil, I end up with around 5.25 - 5.5 gallons in the fermentor and around a quart of material leftover in the whirlpool. This never varies and did not for these two batches.
SG reading error - I cool directly from the kettle through a 30 plate chiller right into the bucket. Although unneccesary, I give the cooled wort a stir when hydrometer goes into bucket so I am quite certain that it is not a lack of wort mixing error. Also, for the hefe I made yesterday, I placed 2 hydrometers into the wort (hoping one suddenly went bad) and both came back the same: 1.044 (where my other 90+ batches read 1.054 - 1.058 for 11 lb grain bills). So, that rules out mixing & hydrometer errors.
Temperature - This is what I thought my problem was a couple weeks ago. So, I borrowed a certified glass thermometer from work (I work in a scientific equipment company and we have lots of labs) and calibrated all my thermometers using 150oF water (as measured by glass thermometer). I found out that my 'trusted' thermometer was 10 degrees low. That made me happy to find that. I also found that one of my other digital thermometers was spot on. So, for this batch, using my calibrated thermometers, I thought my temporary low eff batch was a one off due to low temps and was now in my rear-view mirror. Nope, that wasn't it. Got the same results and I know that my 152oF mash WAS a 152oF mash (as measured in different locations in the thoroughly mash using two calibrated thermometers). For fun, I measured the temp of the boiling wort and the calibrated thermometer read exactly 212oF.
Mash time - I mash for 90 minutes. Always have. I maintain a 90 min mash with NO loss in temps, even in the winter (I cover the cooler with my super-insulated ice fishing jacket). Also, my recently calibrated go-to thermometer is a turkey fryer thermometer. I drilled a small hole in the lid of my cooler a long time ago and insert this long thermometer through the lid and into the mash. I've done this since 2007 and I am confident that this reflects accurate temps.
So, I am at a loss why suddenly, with no changes at all to my brewing ingredients, process, or measurements, I have suddenly lost this much efficiency. I am an analytical chemist by training and as such I fancy myself a decent troubleshooter (I did tech support for 7 yrs) and I understand how to use design of experiments (DoE) to track down cause & effect. Also, I've been reproducibly making beer for some time so I kinda know what I am doing.
What have I missed?