Final abv consistently low

Cliffy&Norm

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I have a Vevor brewing system and have been doing this for almost 2 years. My beers always come out .5%-1% lower than anticipated. My beers turn out a little sweeter than anticipated. I assume the yeast isn't eating the sugars up enough since I'm usually doing LME brewing. I ferment right around 70 degrees and have recently bought a fridge to help control that temperature and a heat wrap. My only guess is that I haven't been controlling my fermentation temp good enough since I would throw it in a dark closet for two weeks then keg or bottle it.
 
Have to ask…how are you measuring gravity? Hard to believe a yeast wouldn’t fully ferment an all extract wort.
 
My beers always come out .5%-1% lower than anticipated.
If you could provide a couple of recipes, including specific brands of LME, along with measured OG/FG/ABV, that should be helpful in troubleshooting the problem.
 
I had issues with extract not fermenting below 1.020. That is mostly why I went BIAB. The first time I did grain, my FG was normal. I have a feeling it is your extract. If that is the only way you feel comfortable, you might try steeping some base malts.
 
I assume the yeast isn't eating the sugars up enough since I'm usually doing LME brewing.
That is the most likely reason. Years ago when extract brewing was predominate, people would add 1/2 to 1 pound of sugar to "dry" the beer out. The sugar boosts the gravity without any unfermentable sugar, leaving the gravity and sweetness lower in the final beer.

I have been all grain for nearly 14 years. A while back I did an extract version of one of my regular beers. It reminded me that when I went to all grain the beers were dryer and "brighter". If you can, try a simple all grain recipe. Pitch a pack of your favorite dry yeast per 5 gallon and see if it makes a difference.

Happy brewing!
 
While we're waiting for OP to return, I'll mention that I currently brew a mix of BIAB & 'extract' (mostly DME, occasionally LME) and I have never had an 'accidental' FG 20 when brewing DME/LME.
 
If you could provide a couple of recipes, including specific brands of LME, along with measured OG/FG/ABV, that should be helpful in troubleshooting the problem.
Here's one I just made up and punched into
If you could provide a couple of recipes, including specific brands of LME, along with measured OG/FG/ABV, that should be helpful in troubleshooting the problem.
Here's one I made up using this site. I order from northern brewer or more beer typically so ingredients should be good... I do believe my OG is on the low side consistently but why?..

Title: Strong Ale 7 gal

Brew Method: Extract
Style Name: American Strong Ale
Boil Time: 60 min
Batch Size: 5.5 gallons (fermentor volume)
Boil Size: 7 gallons
Boil Gravity: 1.043
Efficiency: 25% (steeping grains only)

Hop Utilization Multiplier: 1

STATS:
Original Gravity: 1.067 -- Actually was 1.054
Final Gravity: 1.017 -- Actually was 1.015
ABV (standard): 6.5% -- Actually was 5%
IBU (tinseth): 34.83
SRM (morey): 20.59
Mash pH: 0

FERMENTABLES:
7.5 lb - Liquid Malt Extract - Light (65.2%)
1 lb - DME Sparkling Amber - (late boil kettle addition) (8.7%)
1.25 lb - Brewers Crystals - (late boil kettle addition) (10.9%)

STEEPING GRAINS:
0.5 lb - American - Special Roast (4.3%)
1 lb - United Kingdom - Brown (8.7%)
0.25 lb - United Kingdom - Chocolate Malt (2.2%)

HOPS:
0.5 oz - Chinook, Type: Pellet, AA: 13, Use: Boil for 60 min, IBU: 23.9
1 oz - Perle, Type: Pellet, AA: 8.2, Use: Boil for 10 min, IBU: 10.93

YEAST:
Wyeast - American Ale II 1272
Starter: No
Form: Liquid
Attenuation (avg): 74%
Flocculation: High
Optimum Temp: 60 - 72 F
Pitch Rate: 0.35 (M cells / ml / deg P)

PRIMING:
CO2 Level: 2.25 Volumes
 
Speculation: a stratified wort when using partial boils with late additions?
eta: or dead space in the AIO that isn't reflected in the recipe calculations?

Final Gravity: 1.017 -- Actually was 1.015
So not stuck at OG 20. Looks like actual attenuation was 72% so the yeast were probably working OK.

1723761241546.png


Original Gravity: 1.067 [...]
What is your brewing process?

If you are brewing with a "partial boil" with late additions of extract and water (start with 2 gal water in the fermenter, add the wort, then "top off" to 5.5 gal), there is a claim that the wort is often stratified and OG measurements will be inaccurate.

I wrote this section before realizing I overlooked the "partial boil" process consideration. I'll leave it here in case it's not a partial boil.
Original Gravity: 1.067 [...]
I re-estimated OG for the ingredients listed and got OG 67.

Original Gravity: 1.067 -- Actually was 1.054
With extract, assuming
0) the wort is not stratified
1) the recipe estimates are accurate
2) all the ingredients are added
3) the SG measurement is accurate
OG will be +/- a couple of points.

OG 54 is 72 "gravity points" short. That's either
1) missed adding roughly 2# LME or 1.5# DME
2) an extra 1.25 gal water
3) an SG measurement that's not accurate
4) stratified wort
5) or some combination of the above

In this situation, the next step would be verify the SG measuring tool is accurate and that volume measurements are accurate.
 
Last edited:
I wonder if you are getting gravity points in the software from the steeping grains. They may not convert into fermentable sugars. Try removing them from the recipe editor and see if your gravity prediction is closer to what reality was. If that is the case, increase your malt extract to get the gravity you are looking for.
 
Yeah @Craigerrr ! Just because the recipe says that your OG should be 1067 doesn't guarantee the ingredients you put together is going to have the same gravity points. I thought maybe the yeast was older and losing its vitality for a higher gravity brew but you got the 1050 down to a respectable 10 teen figure so maybe the OG starting line needs to be recalculated for your specific grain bill and extracts.

A quick fix could be just toss in some more extract in the boil if it's not up to spec. I think there's a calculator tool for just that purpose on the site here.
 
Using PPG values from Brewers Friend, I get an estimated OG of 66 from just the LME/DME/crystals:

View attachment 30194


@Cliffy&Norm : what are your starting and ending wort volumes?
I popped it in BF also and for 7 gallon batch I got your OG. Changing it to a 5.5 gallon to the fermenter was 1.066. I didn’t add the grains. You have a volume issue with your OG.
If you were doing all grain I could see the difference if your mash temperature was off, but with LME/DME I have never seen a difference this high unless an ingredient was forgotten or the volume was off.
 
Speculation: a stratified wort when using partial boils with late additions?
eta: or dead space in the AIO that isn't reflected in the recipe calculations?


So not stuck at OG 20. Looks like actual attenuation was 72% so the yeast were probably working OK.

View attachment 30191


What is your brewing process?

If you are brewing with a "partial boil" with late additions of extract and water (start with 2 gal water in the fermenter, add the wort, then "top off" to 5.5 gal), there is a claim that the wort is often stratified and OG measurements will be inaccurate.

I wrote this section before realizing I overlooked the "partial boil" process consideration. I'll leave it here in case it's not a partial boil.

I re-estimated OG for the ingredients listed and got OG 67.


With extract, assuming
0) the wort is not stratified
1) the recipe estimates are accurate
2) all the ingredients are added
3) the SG measurement is accurate
OG will be +/- a couple of points.

OG 54 is 72 "gravity points" short. That's either
1) missed adding roughly 2# LME or 1.5# DME
2) an extra 1.25 gal water
3) an SG measurement that's not accurate
4) stratified wort
5) or some combination of the above

In this situation, the next step would be verify the SG measuring tool is accurate and that volume measurements are accurate.
I believe I tried to do a full volume mash which I think you referenced would throw the numbers off... I think for a 5 gallon batch I would need to do about 2.5 gal of water for mash then fill up to 7 gal for the boil. (Lose 1 gal in the boil, transfer 5.5 to fermenter due to the junk left at the bottom, then 5 gallons in the end going into a keg)... Yesterday I tried doing an all grain recipe and did the mash in 5 gallons at 153degrees and had a circulation pump running for the full hour. I then filled up to 7 gallons for boil. I ended up being .03 off on OG which was half the amount... A refractometer is definitely on my list, I use a hydrometer now but want something quicker so I can adjust right away.
 
@Cliffy&Norm : I thought we were talking about the OG issues with the "Strong Ale" extract recipe.

Title: Strong Ale 7 gal

Brew Method: Extract
Style Name: American Strong Ale
Boil Time: 60 min
Batch Size: 5.5 gallons (fermentor volume)
Boil Size: 7 gallons
Boil Gravity: 1.043
Efficiency: 25% (steeping grains only)

With extract, assuming
0) the wort is not stratified
1) the recipe estimates are accurate
2) all the ingredients are added
3) the SG measurement is accurate
OG will be +/- a couple of points.

OG 54 is 72 "gravity points" short. That's either
1) missed adding roughly 2# LME or 1.5# DME
2) an extra 1.25 gal water
3) an SG measurement that's not accurate
4) stratified wort
5) or some combination of the above

In this situation, the next step would be verify the SG measuring tool is accurate and that volume measurements are accurate.

in your latest comment, you are talking about an all-grain recipe (mashing, etc).

I believe I tried to do a full volume mash which I think you referenced would throw the numbers off... I think for a 5 gallon batch I would need to do about 2.5 gal of water for mash then fill up to 7 gal for the boil. (Lose 1 gal in the boil, transfer 5.5 to fermenter due to the junk left at the bottom, then 5 gallons in the end going into a keg)... Yesterday I tried doing an all grain recipe and did the mash in 5 gallons at 153degrees and had a circulation pump running for the full hour. I then filled up to 7 gallons for boil. I ended up being .03 off on OG which was half the amount... A refractometer is definitely on my list, I use a hydrometer now but want something quicker so I can adjust right away.

If you want to go back to talking about the "Strong Ale" recipe that's fine. Otherwise, I'll probably "drop out" of this topic.
 
@Cliffy&Norm : I thought we were talking about the OG issues with the "Strong Ale" extract recipe.





in your latest comment, you are talking about an all-grain recipe (mashing, etc).



If you want to go back to talking about the "Strong Ale" recipe that's fine. Otherwise, I'll probably "drop out" of this topic.
Sorry, I got brewing issues and started talking about my batch last night that was off... I never thought about the dead space in the AIO being the issue. I appreciate your knowledge and time.
 
I never thought about the dead space in the AIO being the issue. I appreciate your knowledge and time.
Thanks for the follow-up!

... and a quick thought on the all grain recipe.
I ended up being .03 off on OG which was half the amount... A refractometer is definitely on my list, I use a hydrometer now but want something quicker so I can adjust right away.
Of by .03 (SG 52 vs SG 55) at end of boil is pretty common. Most of the time, I'll just accept it and move on to the fermenter.
 

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