I keep missing my pre-boil by an average of 15 points. I've been using DME to compensate but I just can't figure out what's going wrong. I do not sparge but I press the grains. My water volume calculations have been off in the past but this last batch was spot on. I normally do a 60 minute mash. Could the grains being pre milled be the issue? Any advice would be great
Missing OG by at least 15
- Thread starter arkayy
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My guess would be your grain crush, can you post a detailed pic showing the crush?
Examine your grist closely, are there any whole uncrushed kernels? Are all the kernels well fractured?
My number one rule for best results mashing...
1. The grain needs to be crushed exposing the starch inside, not cracked, crushed. The water will not get to the grain starches, and the sugar will not magically escape thru the husk, CRUSH!
Examine your grist closely, are there any whole uncrushed kernels? Are all the kernels well fractured?
My number one rule for best results mashing...
1. The grain needs to be crushed exposing the starch inside, not cracked, crushed. The water will not get to the grain starches, and the sugar will not magically escape thru the husk, CRUSH!
radwizard
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I squeeze my grains, and don't use a pulley system (which it sounds like you are doing as well) . On my first BIAB I ended up low on OG. The problem (I assume) was I didn't squeeze it out as hard as I should have. On my second brew I squeezed the grains like a crime scene, and I ended up slightly over. I also re-heated the mash up to 170 and let it rest for ten minutes before the squeeze.
I haven't had an issue with grains being milled. My LHBS does my milling and they have done a good job. I make sure they know I'm doing a BIAB, and stress the double milling to them. No issues there.
Are you squeezing it all out? How are you getting your grains milled?
I haven't had an issue with grains being milled. My LHBS does my milling and they have done a good job. I make sure they know I'm doing a BIAB, and stress the double milling to them. No issues there.
Are you squeezing it all out? How are you getting your grains milled?
pricelessbrewing
Brewer's Friend Software Manager
There's a number of things that could be happening. If you can provide some info on your brewday, I'll run it through my calculator (link in my sig, if you're on mobile then google me) and see what might be causing the issue. Typically it's either the grain crush, or poor sparge practices.
If you're doing no sparge, you may be having slightly less than ideal mash conditions. A slow converstion rate can be attributed to the grain crush, poor ph, the grain crush, very weird water mineral content, poor dough in, overly thick mashes (not a problem for no sparge), and the grain crush. Did I mention the grain crush?
By taking precise measurements at two points, it's really easy to calculate out a ton of information about your system and nail down your consistency.
Take three readings for each data point:
1) gravity (be sure to mix the wort thoroughly before taking a sample to ensure homogeneous gravity throughout, wait for the sample to cool to either 60F or 68F depending on your hydrometers calibration temp)
2) volume (measured! no eyeballing! I use a stainless ruler)
3) Temperature ( necessary to compensate for thermal expansion. Liquids take up more space when they're hotter.)
First data point: First runnings, this occurs after the grain bag is separated from the mash and is done draining (wait till you're done squeezing if you squeeze). This information provides conversion efficiency, mash and lauter efficiency up to this point (if you sparge, then it only provides conversion), As well as grain absorption.
Second data point: Pre boil, in a sparging process this provides total mash and lauter efficiency, and average grain absorption between first and second runnings. Tip: You can use your preboil to calculate the expected post boil gravity, and extend/shorten your boil, or if you're preboil gravity is high you could also dilute the wort slightly to the target preboil OG and end up with slightly more beer. Would need to adjust the hop bill accordingly.
Bonus round: post boil. This should have the same efficiency numbers, but can be used to calculate the apparent and true boil off rate. I like to use preboil volume instead of post boil volume to determine mash efficiency since it has less errors due to hop absorption and hop volume displacement.
If you're doing no sparge, you may be having slightly less than ideal mash conditions. A slow converstion rate can be attributed to the grain crush, poor ph, the grain crush, very weird water mineral content, poor dough in, overly thick mashes (not a problem for no sparge), and the grain crush. Did I mention the grain crush?
By taking precise measurements at two points, it's really easy to calculate out a ton of information about your system and nail down your consistency.
Take three readings for each data point:
1) gravity (be sure to mix the wort thoroughly before taking a sample to ensure homogeneous gravity throughout, wait for the sample to cool to either 60F or 68F depending on your hydrometers calibration temp)
2) volume (measured! no eyeballing! I use a stainless ruler)
3) Temperature ( necessary to compensate for thermal expansion. Liquids take up more space when they're hotter.)
First data point: First runnings, this occurs after the grain bag is separated from the mash and is done draining (wait till you're done squeezing if you squeeze). This information provides conversion efficiency, mash and lauter efficiency up to this point (if you sparge, then it only provides conversion), As well as grain absorption.
Second data point: Pre boil, in a sparging process this provides total mash and lauter efficiency, and average grain absorption between first and second runnings. Tip: You can use your preboil to calculate the expected post boil gravity, and extend/shorten your boil, or if you're preboil gravity is high you could also dilute the wort slightly to the target preboil OG and end up with slightly more beer. Would need to adjust the hop bill accordingly.
Bonus round: post boil. This should have the same efficiency numbers, but can be used to calculate the apparent and true boil off rate. I like to use preboil volume instead of post boil volume to determine mash efficiency since it has less errors due to hop absorption and hop volume displacement.
On my next brew day I will examine and post a picture of the milled grain. I get them through morebeer.com so I'm not sure if anyone has had problems with their grains. I'll definitely try raising to temp to 170 before removing the bag to press it. I am assuming I press it enough, I use a small pot lid and put almost all of my weight into it. Thanks for all of the advice I'll post an update after my next brew day.
On my last brew, I dramatically increased my efficiency.... It was about 13lbs of grain, I had the LHBS mill it and then I remilled it at home with my cheap cereal grinder. It was fairly fine which seems to work well for BIAB. I exceeded my planned OG so have adjusted my recipe for this improved efficiency. I'll see how that works soon by repeating the same procedure with the adjusted recipe.
GearDaddys
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This is an interesting question that I've had regarding HomeBrew shops who sell pre made "all grain kits".. The homebrew store (MoreBeer, whom I LOVE) is using a specific setup to achieve whatever they are advertising their gravity readings to be.. You buy the kit, but your brew day/equipment etc is ALL different.. There is virtually no way that you are going to come up with the same numbers as they are.. Conversely, if you use brewing software such as BeerSmith (No offense Priceless, I'm not even sure if your calcs can do conversions such as this) you can enter a recipe, enter the authors brew house efficiency, then have the software tweak the ingredients to match YOUR specific efficiency.. It seems like with these "all grain kits" you kinda get what you get.. Of course the crush, and PH matter.. I have a grain mill and crush the CRAP out of my grains.. even so, I'm usually coming in at 68-72 percent.. I've been tempted to try some of these all grain kits in the past.. This thread makes me think I'll stick to my regular routine!
pricelessbrewing
Brewer's Friend Software Manager
Not affected at all. While I do estimate each efficiency accurately (and do so better than bs2 in my biased opinion) , I don't currently have a recipe builder section, working on it probably next week, at which point I'll add a scaling tool. Will be a fun experiment.
Another issue with kits is that they tend to produce all kits at the same 70% efficiency, regardless of grain bill. This is not realistic at all. Setting aside differences in equipment and process, there's no way the same system can do a 1.090 Ris at the same 70% as the 5% american pale ale kit. Doing so is just setting up your customer for disappointment when their 9.5% ris turns out into 8.2% because they're too lazy to understand how grain bill affects the process.
The quality of the milling of the grains is the usual cause of low efficiency. Until you get your own mill, you are at the mercy of the ones who mill your grain and they are more concerned about the conventional tun users getting a stuck sparge and complaining or going somewhere else to buy their grains than they are with milling for the best efficiency. Go ahead and blow your tax refund on a grain mill. Set it to mill as fine as you can get the grain to go through and watch your efficiency go up.
