my final gravity is consistantly low

[apshaffer]

I brew all grain. Usually hit my mash temp within a degree or two. Mash for 60+ minutes. I hit my target volumes and original gravity within a few points. But, my final gravity is consistently low. My last batch was 10gal of hefe. Mashed at 153. OG was 1.051. I used wyeast 3068. Fermented in the low 60's for 20 days. No secondary. Target FG (according to beersmith) was 1.013. Mine was 1.004. Before the hefe, my esb was targeted to finish at 1.014. Measured FG was 1.008. I'm consistently 5-10 points low, no matter the style, yeast used, OG, etc. Doesn't matter if its an ipa or a pils. I'm always low.

Is it an issue with the mash? I'm positive my thermometers are calibrated...I had our micro bio lab at work do it. My mash efficiency seems fine...consistently in the upper 70s.

I'm curious how other folks hit target FGs, or if they just let the yeast run its course. Or, do you keep checking gravities and rack off the yeast when you hit your number? Or, is there something I can do in the mash? I'm not worried about it, just curious.

 

[RM-MN]

I brew all grain. Usually hit my mash temp within a degree or two. Mash for 60+ minutes. I hit my target volumes and original gravity within a few points. But, my final gravity is consistently low. My last batch was 10gal of hefe. Mashed at 153. OG was 1.051. I used wyeast 3068. Fermented in the low 60's for 20 days. No secondary. Target FG (according to beersmith) was 1.013. Mine was 1.004. Before the hefe, my esb was targeted to finish at 1.014. Measured FG was 1.008. I'm consistently 5-10 points low, no matter the style, yeast used, OG, etc. Doesn't matter if its an ipa or a pils. I'm always low.

Is it an issue with the mash? I'm positive my thermometers are calibrated...I had our micro bio lab at work do it. My mash efficiency seems fine...consistently in the upper 70s.

I'm curious how other folks hit target FGs, or if they just let the yeast run its course. Or, do you keep checking gravities and rack off the yeast when you hit your number? Or, is there something I can do in the mash? I'm not worried about it, just curious.

I'll believe that your thermometer is accurate but have you calibrated you hydrometer? Try it in water and see what your reading is. It should be 1.000 in distilled water. It should be close to that in tap water too.

 

[JustLooking]

How do you mash (BIAB, insulated cooler, RIMS/HERMS....) and what are you using to measure mash temperature? Thinking that there may be temperature stratification developing during the mash if you can't measure every place in your tun.

I will normally run about 5 points below Beersmith's estimate, but 1.004 is pretty crazy!

 

[FourSeasonAngler]

Agree, calibrate your hydro. If that is correct then double check the accuracy of your ferm chamber thermometers. Sounds like high ferm chamber temps could be a problem too if you're only regulating the temps based on air temp and not internal wort temp. If your ferm chamber is sitting at 65F through the whole primary your wort could be reaching 72+F during active fermentation.

 

[JustLooking]

Something to keep in mind is that hydrometer reading are usually linear, so if it's reading low at FG, it's reading low on OG also.

From my experience, high fermentation temperature will cause lots of activity followed by stalling above my predicted FG. If it drops from there, chances are that there are other bugs at play.

 

[blizz81]

Thinking that there may be temperature stratification developing during the mash if you can't measure every place in your tun.

This would be my guess given you mentioned you hit your mash target temps but did not mention you do any temp measurements outside of (presumably) dough-in.

 

[apshaffer]

I have never calibrated my hydrometer. I will do that. But if hydrometer readings are linear, I should be reading low OGs as well.

I mash in a 10 gallon round cooler. I measure my mash temp with a lab-grade digital thermometer with a long probe, maybe 8" long. The mash is well stirred. I measure temps after I stir, about 15 minutes into mash, and at the end. I lose about 2 degrees after 60 minutes.

My fermentation chamber is a closet in my semi-heated garage. I am at the mercy of ambient temperatures. That being said, I live in western Washington. Its relatively mild here...I would say there's only a few degrees difference between the high and low daily temps in my garage. I have a thermometer out there, one of those inside/outside ones. I have no idea how accurate that is.

 

[MoanaDrifter]

I had the same problem over several batches and jacked the mash temp all over the place trying to fix it (and making some pretty bad beer in a batch or two in the process) with the same result. Turned out to be an infection. A good scrubbing of everything with bleach water on the fermentation side of the boil fixed it and now my FGs are consistently where I expect them to be.

 

[apshaffer]

I checked my hydrometer with tap water and it reads 0.096. So it is a little low. I checked my last 12 batches and every one is 5-10 points lower than beersmith estimates, but I have hit or overshot my OG by a few points.

 

[apshaffer]

Maybe I have been overshooting my OGs and measuring them low, but thinking they are accurate.

 

[RM-MN]

Maybe I have been overshooting my OGs and measuring them low, but thinking they are accurate.

Congratulations on getting better brewhouse efficiency than you had planned on.

We tend to buy expensive thermometers to get to the exact mash temperature but measure our results with a cheap hydrometer that has a paper scale slid up into it thinking that we are measuring with great accuracy but sometimes the paper scale slips. It's part of being a home brewer. Go get yourself a couple new hydrometers and check them for accuracy before you brew again. :rockin:

 

[bhanson]

How does the beer taste?

 

[winvarin]

One other thing to consider is your post mash process. Two questions:

1. Do you raise the temp of your grain bed out of the sacc. range before sparging, I.e mash out.

2. Once you start collecting your runnings, how soon do you get them on the burner?

I ask both because if you're leaving your bed at mash temp while sparging, you may still be converting starches to sugars and a larger number of your long chain sugars to shorter ones. I sometimes intentionally skip mash out to increase the fermentability of a beer I want to finish dry, like a Saison.

Question 2 is part B of this. If you don't mash out and you leave your pot of wort at 140-150-ish while collecting runnings, there is still enzymatic action going on in the kettle and increasing the fermentability of the wort.

In most cases, once I collect about 50% of my pre-boil volume, I get it on the heat while collecting the rest. It shortens my time to get to boiling and gets the wort out of sacc. temp. range faster.


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[apshaffer]

The beer always tastes fine. I'm not really concerned about low FG, more curious. If its a technique issue, I'll try to correct it.

I don't mash out on my first runnings. I don't have the volume to end conversion with my first runnings still in the MT. But, I sparge with water hot enough to stop conversion. I heat my sparge water up as I'm draining my first runnings. As soon as its drained, I add my first run of sparge water at near boiling. That'll bring the grain bed to a little over 180. I stir, stir, stir, let that rest for 15-20 minutes, drain, then repeat with more sparge water to get to my planned volume. I drain my first runnings directly into my boil kettle. It goes on the burner directly, but on med/low. I turn it up after I add my first sparge, once I get about 2/3 of my total pre-boil volume.

 

[Talgrath]

Are you hitting your pH? If your pH is tending more towards the high end it may be more fermentable than expected. I also noted that you ferment approximately 20 days, keep in mind that BrewKrauser may be based on manufacturer's expected fermentation time, longer fermentation may decrease the FG. I usually ferment for 14 days at a minimum and my FGs are usually a little bit lower than expected as well.

 

[user 141939]

One other thing to consider is your post mash process. Two questions:

1. Do you raise the temp of your grain bed out of the sacc. range before sparging, I.e mash out.

2. Once you start collecting your runnings, how soon do you get them on the burner?

I ask both because if you're leaving your bed at mash temp while sparging, you may still be converting starches to sugars and a larger number of your long chain sugars to shorter ones. I sometimes intentionally skip mash out to increase the fermentability of a beer I want to finish dry, like a Saison.

Question 2 is part B of this. If you don't mash out and you leave your pot of wort at 140-150-ish while collecting runnings, there is still enzymatic action going on in the kettle and increasing the fermentability of the wort.

In most cases, once I collect about 50% of my pre-boil volume, I get it on the heat while collecting the rest. It shortens my time to get to boiling and gets the wort out of sacc. temp. range faster.


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I was gonna post something along these lines. Definitely worth thinking about. I try to keep my sparge water fairly hot because it takes me a half hour or so to sparge and I don't want my temp to drop too much, thus thinning my beer post ferment.


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[pdietert]

I add my first run of sparge water at near boiling. That'll bring the grain bed to a little over 180.

Watch that sparge water temp, anything over 170 hitting the grain bed will be extracting quite a bit of tannins.

A heffe with a FG of 1.004 is going to be very dry. Is it dry? An ESB at 1.008 is not too bad, the low end of the normal scale but it will be a bit dry. Is it dry?

Are you adjusting your gravity readings for temperature?

Are you using a refractometer?

Getting better efficiency from Beersmith and Brewers Friend is not unusual. Both use the middle of the range of a yeasts expected attenuation.

 

[duboman]

First off, FG numbers on a recipe are a guideline, estimate only based upon what the software determines and may not be the actual result.

Second, at 1.004 I would correlate that to low mash temps and highly fermentable wort or poor recipe design. Mash pH is important for proper conversion. If you are really finishing that low I don't think pH is an issue.

You are batch sparging from your description so there is no "mash out" step. If you were fly sparging I would then be concerned you are still getting conversion during the sparge but not if you are adding near boiling water to batch sparge. Also, tannin extraction is a function of both pH AND sparge temp together. If you mashpH was off then tannin extraction could be an issue. If you are not tasting any astringency issues with your beer then you can eliminate this problem.

If your thermometer truly is a calibrated lab quality device then mash temp should be ruled out assuming no stratification or huge temp loss. In a good mash environment conversion usually occurs within the first 30 minutes so if you are not losing 2+ degrees in that time it shouldn't be that big a deal affecting fermentability.

You have already determined your hydrometer is off so that needs to be corrected. As RM mentioned 1.000 in distilled water at its calibration temp which should be printed on the paper somewhere so be sure that is correct.

The only other thing I can add is to verify your volumes. If you are simply working off printed buckets, verify the markings with actual measured volumes, I have several buckets that are not correct. Otherwise I have to go back to your thermometer with such a large discrepancy in estimated to actual, The FG's are usually associated with low mash temps and highly fermentable wort.

 

[apshaffer]

I didn't check my pH on this batch, but it has always been in the ball park when I have checked it. After checking the pH more than a dozen batches and it being close, I stopped.

I sparge as soon as my first runnings are drained. 180 was a typo, I use water at around 200 degrees to bring my grain bed to a little over 170. Depending on the amount of grain, it may only raise it to 168 or so. I do 10 gallon batches, so the sparge water needs to be that hot to raise the temps of that amount of grain. I have never noticed any issues with tannins.

I'm not sure if this hefe is dry, I just kegged it a few days ago. Its the same recipe as I've always made and they were not dry, although the last 2 finished at 1.008 (still low for the style). The esb was not dry. Some of my other beers were dry, but by design. I make a lot of pales, pils, and ipa's. I am not using a refractomoter. I have a hydrometer, but apparently it reads low.

The hefe recipe is 60% wheat, 40% pils with about a pound of rice hulls for drainage. Pretty traditional hefe recipe. All my recipes are traditional, and they all seem to finish low...well maybe, according to beersmith and a crappy hydrometer. A mash temp of 153 seems on the high end for a hefe to me. This batch started at 153.7 and finished at 151.5 after an hour. My volumes are correct. My fermenter is a 13 gallon graduated food grade nalgene bottle, and I've double checked the volume markers.

I thought there may have been an issue with my mash technique, and there may be. I think the issue is me taking brewing software/BJCP numbers as gospel, and an uncalibrated hydrometer. My beers always turn out good. Other home brewers think so, and a few professional brewers I know think so. My numbers just aren't where they should be according to beersmith and the BJCP...or maybe they are...that's what I'm not sure about. There has been no issue with the beer itself.

 

[pdietert]

Sounds like you need a new hydrometer.

 

[cokerwk]

One other thing to consider is your post mash process. Two questions:

1. Do you raise the temp of your grain bed out of the sacc. range before sparging, I.e mash out.

2. Once you start collecting your runnings, how soon do you get them on the burner?

I ask both because if you're leaving your bed at mash temp while sparging, you may still be converting starches to sugars and a larger number of your long chain sugars to shorter ones. I sometimes intentionally skip mash out to increase the fermentability of a beer I want to finish dry, like a Saison.

Question 2 is part B of this. If you don't mash out and you leave your pot of wort at 140-150-ish while collecting runnings, there is still enzymatic action going on in the kettle and increasing the fermentability of the wort.

In most cases, once I collect about 50% of my pre-boil volume, I get it on the heat while collecting the rest. It shortens my time to get to boiling and gets the wort out of sacc. temp. range faster.


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I'm going to have to agree with Winvarin. I was having a similar issue with my FG's being lower than expected, and after trying new thermometers and hydrometers, I decided to turn the heat on the kettle after collecting a couple gallons of wort. I was also having a difficult time hitting my mash out temp (always a few degrees short), but once I started applying heat to the kettle during the wort collection, my FGs fell in line. Apparently conversion was still going on and my mash out wasn't enough to stop conversion.

Since, I'm doing a better job with mashing out, but I still start heating the kettle after a gallon or two of wort collection. If nothing else, it speeds up the brewing day. And my FG is correct.

 

[apshaffer]

My attempt at stopping conversion with the addition of the first sparge water may be inadequate. My wort is obviously more fermentable than I expect, but not as much as I'm recording, due to my poorly calibrated hydrometer.

I have been researching options for HERMS and RIMS systems to bring mash up to mash out temps. I could probably make a HERMS system with stuff I have already, minus any electronics. I may go that route. Not sure. It would be nice to have the ability to do step mashes.

 

[andy6026]

Did I read that correctly that your hydrometer in water reads 0.098?

You definitely need a new hydrometer.

Another thing that I don't think anyone's mentioned is that if you are mashing too long then it will increase the fermentability of the wort. You mentioned you typically mash for 60+ minutes. 60 is about the average mash lengths for most recipes, but if you find that they are coming out too dry after you've got a new hydrometer, then you may want to try a batch where you mash for less time, say... 45 minutes.

 

[FourSeasonAngler]

Depending on how long your vorlauf/lauter & sparge is, the biggest factor I see is that mash-out.

You should use a mash-out calculator to give you the amount of near boiling sparge water (treated to avoid tannin extraction) you need to add to bring your grain bed up to 170 degrees for your sparge.

For the first few all-grain batches I brewed this was (one of) my issues I had to deal with. My resulting beers were always dry, and over attenuated. When I first went to tackle this problem I tried to increase the % of crystal malts and dextrine malts thinking that my recipes were off. Foolish of me since most of my recipes were previously tested and brewed. That's how we learn though...

 

[blizz81]

Depending on how long your vorlauf/lauter & sparge is, the biggest factor I see is that mash-out.

You should use a mash-out calculator to give you the amount of near boiling sparge water (treated to avoid tannin extraction) you need to add to bring your grain bed up to 170 degrees for your sparge.

For the first few all-grain batches I brewed this was (one of) my issues I had to deal with. My resulting beers were always dry, and over attenuated. When I first went to tackle this problem I tried to increase the % of crystal malts and dextrine malts thinking that my recipes were off. Foolish of me since most of my recipes were previously tested and brewed. That's how we learn though...

Interesting it had that much of an impact. From what I've seen, beta is pretty well denatured after about 158*F. Even if you were more at the beta range for a mash, I would think it wouldn't take much to raise the bed to at least that temp even if you missed say, 168-170F. But I suppose it's not ALL the way denatured until around 170.

 

[TexasWine]

Did I read that correctly that your hydrometer in water reads 0.098?

You definitely need a new hydrometer.

Another thing that I don't think anyone's mentioned is that if you are mashing too long then it will increase the fermentability of the wort. You mentioned you typically mash for 60+ minutes. 60 is about the average mash lengths for most recipes, but if you find that they are coming out too dry after you've got a new hydrometer, then you may want to try a batch where you mash for less time, say... 45 minutes.

I'm not sure that a shorter mash will help. Several of us in here that BIAB have been experimenting with shorter mash times (30 minutes and less) and I don't think anyone has seen a reduction in "fermentability" until about a 10 minute mash.

Personally I have used a 30 minute mash the past few batches and FGs have all hit around 1.012, but the predicted FG was around 1.020. Mash temps were 150-152F.

 

[apshaffer]

My hydrometer reads .096 in my tap water. So, it off quite a bit. I haven't tried it in distilled water.

When I say I mash for 60+ minutes, its pretty close to an hour. I may go 10 minutes over, depending on if I get distracted. But, I try to start my vorlauf after 60 minutes.

I use a 10 gallon round cooler for my mash tun. With 20lbs of grain and the initial volume of strike water, there's very little room left to add water for a mash out. I'm looking into ways I can mash out. I could always buy a bigger cooler, but I don't want to do that. I could mash thicker, leaving more room for mash out water. I could start my kettle earlier while I'm draining my first runnings. Or maybe I should just bite the bullet and build a HERMS or RIMS system, and as a bonus, I could step mash. I'm pretty sure I stop conversion when I add my first addition of sparge water (I double sparge), but that's only half the pre-boil volume. The first runnings are the sweetest wort, and they are probably still converting while I'm sparging.

 

[blizz81]

I use a 10 gallon round cooler for my mash tun. With 20lbs of grain and the initial volume of strike water, there's very little room left to add water for a mash out. I'm looking into ways I can mash out. I could always buy a bigger cooler, but I don't want to do that. I could mash thicker, leaving more room for mash out water. I could start my kettle earlier while I'm draining my first runnings. Or maybe I should just bite the bullet and build a HERMS or RIMS system, and as a bonus, I could step mash. I'm pretty sure I stop conversion when I add my first addition of sparge water (I double sparge), but that's only half the pre-boil volume. The first runnings are the sweetest wort, and they are probably still converting while I'm sparging.

That's a good thought. You did say you get the first runnings on heat but I guess there's still some time there before that will get up near 170.


If you do go down the recirc route and want to mash out and / or step mash, from what I've read, HERMS might be better. But I'd encourage you to do your own reading as far as how quickly people are able to raise temp to step. Really on both, it seems pretty common that it's tough to raise temp quickly enough for step mashing to be very effective.


On a RIMS (where more of my reading was / what I wanted to build) I think you're definitely going to be in 240V land if you want to step, and while it seems ULWD elements help avoid scorched wort, where I saw people having problems with it was when they were pushing the elements either in step mashing or mashing out. My 1500W 120 with moderate flow rate, pretty short hose runs, and insulated keggle bumps around 1 degree a minute, but I'm afraid of having the element work hard for 15-20 minutes at a time, and in the case of a mash out as you're wanting to do here, I'm not sure it would beat putting the first wort on heat separately.


Quick search on HERMS and raising temp, I think there's more potential success there in terms of raising temp more quickly without having the wort pass directly over an energized element.