I have been brewing for long time but a few years back I started to see that my OG had been creeping up and my FG is alway 4-5 points lower than the target. I know the first one is a result of having an efficient system (all grain, 13 gal boil) but the FG? I might attribute the OG creep to using more bottled water (we have high Nitrates on tap water) but the FG says that I am over converting my sugars to alcohol? I do use a yeast starter prepared in advance of pitching using DME and dry yeast (2 packs for the 10 gals fermented). Any suggestions would be helpful. I just brewed a Pilsner targeting 4.73% ABV and wound up with 6.43%. Yikes!! Any thoughts?
OG a bit high and FG low
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Just curious. You say your FG is always “4-5 points lower than the target”. How are you determining the target FG? Most brewing software will just shoot the middle attenuation of any particular yeast’s range.
There could be a lot of reasons for a lower than expected FG (long, low temp mashes, high fermentation temperature, very fermentable wort, bad hydrometer/inaccurate readings etc), but I’m just curious if all of these FG’s have been within the yeast’s typical attenuation range (on the high end). In other words, if a yeast has an attenuation range of 75-83%, are you always at 83%, or are you blowing past the high end? If the latter, you might have some wild yeast hitchhiking on your equipment.
There could be a lot of reasons for a lower than expected FG (long, low temp mashes, high fermentation temperature, very fermentable wort, bad hydrometer/inaccurate readings etc), but I’m just curious if all of these FG’s have been within the yeast’s typical attenuation range (on the high end). In other words, if a yeast has an attenuation range of 75-83%, are you always at 83%, or are you blowing past the high end? If the latter, you might have some wild yeast hitchhiking on your equipment.
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For simplicity, Don hit it right on the nose. For the sake or argument, have you changed the brand of the DME?
1) Check your mash thermometer in both ice water at 32 F and boiling water which is likely not exactly 212 F but check to see what it is at your elevation above sea level. Your mash temperatures are partway in between so taking the average deviation will be approximately correct. I know for my mash thermometer it is low by about 2 degrees on one end, but high by about 2 degrees on the other end, which means on average it reads pretty much perfectly at mash temperatures. Many people will not be so lucky and have to add or subtract a couple degrees at mash temp. If you are mashing a few degrees cooler than you thought, then beta amylase will have more time to act before it is denatured, resulting in lower FG than expected.
2) Check also that your hydrometer reads exactly 1.000 in plain cool water. Mine is often off by a couple of points. If it reads 0.998 for example then you need to add 2 points to all readings to get accurate results.
3) Yeast matters a lot. If you are using US-05, its average attenuation is like 83-84% or thereabouts. If you believe you are using "Chico" or "Cal Ale", realize that none of the "Chicos" are actually equivalent but have diverged quite a bit, and most of them attenuate only in the 70s percentage-wise, not 84%. And this is just one example. If you don't want low FG or high ABV, then consider switching to a lower attenuating yeast.
Those are just the first few ideas from my brain. NOT generated from AI but when AI eventually gets smart enough it will hopefully start saying the same stuff.
P.S. OP said he is brewing all grain. Just because he uses DME to make yeast starters, don't assume he is an extract brewer!
2) Check also that your hydrometer reads exactly 1.000 in plain cool water. Mine is often off by a couple of points. If it reads 0.998 for example then you need to add 2 points to all readings to get accurate results.
3) Yeast matters a lot. If you are using US-05, its average attenuation is like 83-84% or thereabouts. If you believe you are using "Chico" or "Cal Ale", realize that none of the "Chicos" are actually equivalent but have diverged quite a bit, and most of them attenuate only in the 70s percentage-wise, not 84%. And this is just one example. If you don't want low FG or high ABV, then consider switching to a lower attenuating yeast.
Those are just the first few ideas from my brain. NOT generated from AI but when AI eventually gets smart enough it will hopefully start saying the same stuff.
P.S. OP said he is brewing all grain. Just because he uses DME to make yeast starters, don't assume he is an extract brewer!
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Boy! A lot to consider here. I do tend to run over on the mash time. Also, I did recently change my DME to a pilsner variety of late. Will check my measuring tools for accuracy. Yes. I use US-05 on my pale and IP ales. This last one was obviously a lager yeast Thanks for the help!!
