Final Gravity is usually low. Should I worry about it.

[Bad Bubba]

I usually brew ales but it seems no matter what I brew, my brews tend to end lower than the projected final gravity. Typically, I am between 1.005 and 1.008. I am using a Tilt, a refractometer, and a hydrometer and they all show the same result so I know that it is not an instrument issue. The result is my beer usually ends a little on the dry side.

So my questions are:

1. Should I even worry about this in the first place?​

2. Is there a way to control the final gravity?​

3. How is the final gravity being projected?​

I do have temperature control on my fermenter.

 

[rsquared]

All grain or extract? Can you give some specific examples of recipes and OG where you had this issue?

1. Only worry if you don't like how dry the beers is. It's not a problem per se.
2. Yes, there are things you can do to tweak it. It depends on recipe and your current process.
3. This follows from 2. Recipe calculators will use the recipe and process you tell it, including mash temp, grains, yeast selection, etc to guestimate the attenuation.

 

[day_trippr]

Calibrated your mash thermometer?

Cheers!

 

[Bad Bubba]

All grain or extract? Can you give some specific examples of recipes and OG where you had this issue?

1. Only worry if you don't like how dry the beers is. It's not a problem per se.
2. Yes, there are things you can do to tweak it. It depends on recipe and your current process.
3. This follows from 2. Recipe calculators will use the recipe and process you tell it, including mash temp, grains, yeast selection, etc to guestimate the attenuation.

All-Grain. I do BiaB and insulate the kettle after it gets to mash temp. Holds to within 2 degrees over an hour.

I am doing an IPA right now with an OG of 1.064 and my FG is at 1.007. I mashed at 154 F.

I mill my own grain but not superfine.

Calibrated your mash thermometer?

Cheers!

I have calibrated - I use thermopens and check against each other.

I know my instrumentation for Temperature and SG are dialed in, and I usually try to mash at about 154.

 

[MikeCo]

1. Worry? Not necessarily. But you may want to understand.
2. The things I have found out impact FG most are:
Ingredients - crystal malts and grains other than base malts in the mash that are not highly fermentable will increase FG. Simple sugars will reduce FG. Some yeasts are more highly attenuative than others.
Mash temperature - lower generally means lower FG. I mash in the 146 to 148 range if I am brewing a very dry beer.
3. I use BeerSmith or BrewFather to calculate OG/FG based on the recipe, water volumes and mash parameters.

Are your grain bills typically mostly base malt, and do you use any sugar?

Do you stir the mash periodically? If not, I'm wondering if you are measuring at the top of the mash tun, and maybe the temperature is lower below.

Abnormally low FG could also be an indicator of some wild yeast infection.

 

[Bad Bubba]

1. Worry? Not necessarily. But you may want to understand.
2. The things I have found out impact FG most are:
Ingredients - crystal malts and grains other than base malts in the mash that are not highly fermentable will increase FG. Simple sugars will reduce FG. Some yeasts are more highly attenuative than others. Are you
Mash temperature - lower generally means lower FG. I mash in the 146 to 148 range if I am brewing a very dry beer.
3. I use BeerSmith or BrewFather to calculate OG/FG based on the recipe, water volumes and mash parameters.

Are your grain bills typically mostly base malt, and do you use any sugar?

Do you stir the mash periodically? If not, I'm wondering if you are measuring at the top of the mash tun, and maybe the temperature is lower below.

Abnormally low FG could also be an indicator of some wild yeast infection.

Thanks for your reply. I have wondered about the stirring of the mash and having a temp gradient. Base malt is usually 75% plus of my grain bill. On some of my IPAs I am adding about 8 oz of dextrose to achieve a little dryer finish.

One thing I am doing is changing my base malt. I purchase my 2 Row in 50/55 # bags. I have been using a locally grown and processed malt and I just purchase a bag of Rahr 2 row and will see if there is a difference.

As my experience grows I want to be able to better control my parameters. One of my projects is to go to eBiaB with recirculation which I hope will result in better Temp control during the mash.

 

[bracconiere]

as a random thought how do you get to 154? do you strike it, or heat slowly?

 

[Dgallo]

When are you dryhoping? Hops contain enzymes that can convert unfermentable sugar into fermentable ones. So if it’s happening just in your ipas that’s what is happening. It’s called hop creep

 

[Bad Bubba]

as a random thought how do you get to 154? do you strike it, or heat slowly?

I am doing Biab so I heat water to a few degrees above mash an then lower the bag into the kettle.

 

[Bad Bubba]

When are you dryhoping? Hops contain enzymes that can convert unfermentable sugar into fermentable ones. So if it’s happening just in your ipas that’s what is happening. It’s called hop creep

I usually dry hop when I get below 1.020 - day 4 or 5. I am familiar with hop creep but this happens in some pale ales where I don’t dry hop.

 

[Dgallo]

I usually dry hop when I get below 1.020 - day 4 or 5. I am familiar with hop creep but this happens in some pale ales where I don’t dry hop.

Well your definitely getting higher than typical attenuation, so if your positive your instrument is working correctly and that it’s not hop creep, are you mashing for longer than 60 minutes?

Did you use a yeast that carries the STA-1 gene? Or have used it recently in a beer or vessel you use for starters?

any off flavors?

 

[Bad Bubba]

I had to look STA 1 up. I was not familiar with that. Not that I am aware of, I use multiple fermenters. I have switched out all of the TC gaskets to new ones.
I am pointing to my base malt at the moment since it is the one constant. I am going to do another IPA in a couple of weeks with a different base malt.
Will boiling the gaskets kill any infections?
No off flavors. My HBC usually likes the beers and they are usually brutal about infections, we have a couple of certified judges in the club.
I have been happy with my beers, I just want to be able to hit the numbers on both ends and maybe get more malt flavor into some of my beers. I am in my 3rd year of homebrewing and feel now I am getting to a point I can move my brewing up a level.

Edit: I mash 60 minutes.

 

[eric19312]

I usually brew ales but it seems no matter what I brew, my brews tend to end lower than the projected final gravity. Typically, I am between 1.005 and 1.008. I am using a Tilt, a refractometer, and a hydrometer and they all show the same result so I know that it is not an instrument issue. The result is my beer usually ends a little on the dry side.

So my questions are:

1. Should I even worry about this in the first place?​

2. Is there a way to control the final gravity?​

3. How is the final gravity being projected?​

I do have temperature control on my fermenter.

You sound data focused so answer to 1 is regardless of whether you should worry about FG you are not going to be able to ignore it.
But I'd say FG 1.005-1.008 is not necessarily a bad place to be.

You mention the beer is coming out dry. Do you mean taste wise or instrument wise? If you really think it tastes dry I'd be curious if tasters that have no knowledge of the FG and your concern about the FG also note it seems dry. Results from a competition would be helpful here since judges don't have knowledge of brewing process or instrument results and are tasting the beer in a lineup of other beers nominally in the target style. But if you don't do competitions at least let your club members try it without telling them about your own thoughts on the beer first.

If the beer is actually coming across as dry I'd then question your water treatment. Might be a matter of tweaking your SO4 / Cl balance a bit more toward Cl.

Finally yes you should be able to control final gravity. Mash higher and add something like carapils or C15-20 are a way to start. Get rid of adjuncts like corn and simple sugar if you are using. And check your thermometer...maybe get 2-3 thermometers and check them against each other like you are doing with your gravity readings. Check temp in the mash in different locations after stirring.

I agree it makes sense to do some extra cleaning to make sure you are not dealing with an infection, happy brew club or not. I do think boiling your gaskets is worth trying. If you have one a pressure cooker is even better. Might also disassemble and clean hot side equipment that contacts the beer on way to fermentor. Ball valves on the brew kettle, pump etc. Oxygen stone if you use one. Obviously new yeast and consider your yeast handling.

 

[bracconiere]

I am doing Biab so I heat water to a few degrees above mash an then lower the bag into the kettle.

pretty much what i do also...but my strike water is usually 15 degrees hotter then my mash in target.....(and my grain is at 80+....)


but i can see if you're doing a full volume mash, wouldn't need to......

and to clarify...so when you lower the grain into the strike water, the temp pretty much is instantly at 150-155f or so?

 

[Bad Bubba]

pretty much what i do also...but my strike water is usually 15 degrees hotter then my mash in target.....(and my grain is at 80+....)


but i can see if you're doing a full volume mash, wouldn't need to......

and to clarify...so when you lower the grain into the strike water, the temp pretty much is instantly at 150-155f or so?

Yes. I usually get a 3 degree drop when I ad the grain. So I heat the water to 157 and add the grain and after I stir it is usually right at 154.

 

[Dgallo]

Yes. I usually get a 3 degree drop when I ad the grain. So I heat the water to 157 and add the grain and after I stir it is usually right at 154.

If this is a 5 gallon batch?. 3 degree drop seems impossible to me. 10-15*f drop would sounds more typical.

if I mash at 154 my strike water needs to be close to 165-168 ish

 

[rsquared]

That depends on volume. 3F does seem a little low, but for full volume mashes (no sparge) I am usually in the 5-7 degree range.

 

[Dgallo]

That depends on volume. 3F does seem a little low, but for full volume mashes (no sparge) I am usually in the 5-7 degree range.

Good catch. I didn’t see the BIAB full volume mash originally

 

[Gregory T]

interesting I brew only Belgians and researching STA 1, I see it is present in nearly every Belgian yeast strain. My beers usually attenuate in the high 80 low 90 range. I make mostly tripels, blondes and saisons..

TBH I don't believe my tripels are dry enough and one of my saisons the judges felt was more akin to a bier de garde even though it came in at 99%

I usually score in the high 30's at competition.

I store my beers at room temp (if anyone wants to build me a cellar, I accept) for long periods and have never had a bottle bomb. I have had some gushers and flats years ago, but that was a priming issue

 

[Bad Bubba]

If this is a 5 gallon batch?. 3 degree drop seems impossible to me. 10-15*f drop would sounds more typical.

if I mash at 154 my strike water needs to be close to 165-168 ish

Specific heat of grain assume - .38 BTU/lb Degree F

11 lb of grain heated from 74 to 154 equals 334 BTU

9 Gallons of water equals 75 lbs. specific heat is 1 BTU/lb degree F - yields about 4.5 degree F delta. These are not exact because I did not correct specific heat changes and I am not sure about the specific heat of Barley - I got it from a google search.

In my system I usually get only 3-4 degree drop. One thing I may need to check it the time to heat transfer to the grain. I usually put in the grain, stir well, then cover and insulate. I do not open the kettle until the mash is done. Usually I only loss one to two degrees during the mash.

 

[PberBob]

Lots of good advice in this thread, for sure.

11 lb of grain heated from 74 to 154 equals 334 BTU...9 Gallons of water

I‘m thinking that’s a pretty high grain/water ratio for mashing. I’ve always worked in the 1.2-1.4 qt/lb range. (limited space in my cooler/mash tun). Not certain, but that could help drive the amylase reactions.
I get fairly low FG’s too, around 1.008 mashing at 152-154 F. My last batch finished at 1.012 after bumping up my crystal-40 from 6%to 10%. Generally, I’m liking the dryer versions.

 

[bracconiere]

I’ve always worked in the 1.2-1.4 qt/lb range. (limited space in my cooler/mash tun).

BIAB'rs steep their grain like a tea bag in the full cup of water though....

 

[Bad Bubba]

Lots or good advice which I appreciate. Many things have been brought up that will help me think things through.

I am definitely working on getting my eBiab system up in running with recirculation so I can control the mash temp better.