Final Gravity finishing too low

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Pete-Hoff

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I recently switched to all grain brewing and have noticed my final gravity reading are much lower than expected. My original gravities are coming in right as predicted and I am very careful about contamination, as I make sure all my equipment is cleaned and sanitized. I have also started using a yeast starter with my batches, that I start 24hr prior to pitching. Any ideas of what might causing the low final gravities? Could it be related to pitching too much yeast as a result of the yeast started? Not sure, just throwing it out there. Appreciate any thoughts you might have.

Thanks.
 
What are you measuring the FG with?

What are your mash temps? Temps can effect starch conversion and leave a less dextrous mash.
 
Pete-Hoff said:
I recently switched to all grain brewing and have noticed my final gravity reading are much lower than expected. My original gravities are coming in right as predicted and I am very careful about contamination, as I make sure all my equipment is cleaned and sanitized. I have also started using a yeast starter with my batches, that I start 24hr prior to pitching. Any ideas of what might causing the low final gravities? Could it be related to pitching too much yeast as a result of the yeast started? Not sure, just throwing it out there. Appreciate any thoughts you might have.

Thanks.
Click to expand...
What sorta FGs we talking ?

Mashing on the low side will make for a more fermentable wort.

You wanna higher FG and Lower overall ABV.

Mash high like 158f and upwards 40mins and I can guarantee that'll fix your higher attenuation problems :)

But as above for more information as Josh and minibari asked will help us help you a bunch.
 
Switching from extract to all grain can bring a lot of changes in the way of flavor and finishing gravities. Most changes are better, I least I think so. For me, extract always seemed to finish sweeter and had a fuller mouth feel. The finish gravities I got accustomed to with extract were different when I switched to all grain. The gravities with grain were lower and the beer had a drier finish, in the end it was a better beer.

That being said, it would be good to know what the apparent attenuation was and what strain of yeast you used. Does the beer taste too thin or does just tastes drier? There are a lot of moving parts to this, so details would be helpful in determining if you have a problem or not and how to correct it if something is wrong.
 
And, the grain crush can make a big difference in BIAB.
My extracts didn't attenuate worth a crap. I was very excited by my first BIAB that actually did finish close to where it was supposed to be.
 
Welcome to all grain brewing! New skills, and details to learn about! Lots of good input from some experienced Brewers above. I would only add that yeast are living organisms, they will do what they do at their own pace. There are ways to plan for higher, or lower final gravity readings, but as long as you are at least close, and the beer is good, I wouldn't sweat it too much.
 
Some info about your mash process - times and temperatures - would help.

I don't think an overpitch would lower the fg except in extreme cases.

How does it taste?
 
Hi all,

So the brew was an American Pale Ale.

Expected OG: 1.057
Expected FG: 1.014
Mash Temp: 152-154
Pre-boil SG: 1.047
Post Boil Gravity: 1.056
Final Gravity: 1.008

Yeast: WLP060

It did taste a little thin but not terrible.
 
Well, White Labs gives an attenuation range of 72-80% for that yeast, and 80% would be about 1.011, so you aren’t that unreasonable at about 86%.

My guess is you just created a very fermentable wort with either the malt you used, the temperature you held, or the length of the mash. Maybe the yeast was at top health, or maybe fermentation ran a little warm.

So many possible reasons why this could have happened and likely none of them are nefarious.
 
Also, the mash was a 1 hr mash, stirring the mash halfway through. 1Tbsp of 5.2 stabilizer in the mash. Strike temp was ~166F. Mash tun is a typical 10gal mash Gatorade cooler mash tun. Batch sparge, temp ~170F.

I have had this happen with a few other brews (Gose and American Amber Ale) and all of them being all grain batches as well.
 
You made a very fermentable wort, and the yeast really enjoyed it! If you feel the need to change anything, just change the attenuation factor so your recipe matches reality. Personally I would continue on with what you are doing, and if you want the ABV to be more in line with planned, adjust you recipe to decrease the OG to suit, that you can control. The yeast, those little buggers, they have a mind of their own!
 
I would also agree, that you mash was probably on the fairly cool side...
Seeing as you know your strike temp, and I would assume mash thickness as well, you can play around with this calc a bit to give you an idea of what your mash temp was: https://www.brewersfriend.com/mash/
I find for lighter lager beers anything lower than 65-65°C starts to attenuate a bit too much for my taste...
 
Pete-Hoff said:
Hi all,

So the brew was an American Pale Ale.


Expected FG: 1.014


Final Gravity: 1.008

Yeast: WLP060

It did taste a little thin but not terrible.
Click to expand...
My question is why did you expect such a high FG? 1.008 - 1.010 is about spot on for an american pale ale. If you're using the recipe designer here, make sure you configure your equipment profile and pay attention to the yeast attenuation rate section as well. This may take some trial and error.
 
When making a big change, like going all grain, it takes a while to dial in your system and process. Everyone's system and process is a little different. It might help to brew the same recipe several times in a row, making small changes each time, to figure out your system. Just because a recipe states "70% efficiency", doesn't mean you'll get the same efficiency. Time and repetition will teach you how your system and process work.
I agree with the people above - an all grain beer usually gets better attenuation than a malt extract beer. And you mash temp can make a difference.
 
If you are having the local brew shop grind the grain there is a good chance the grind will change from batch to batch changing your efficiency each time.
 
Sorry if I've missed some key info in the thread, but if you're using a hydrometer, is your FG sample at 20'C?
 
To be fair a +/- of 20°F only makes a 1 pts difference
 
1.014FG is pretty high, especially for a Pale Ale. I heard Vinnie from Russian River talking about how he aims for 1.010 for IPAs so a touch lower on a Pale Ale seems pretty good!

Your mash temp is slightly lower than the "standard" 67-68C (152-154F), but not crazy at all. A lot of people looking for a dry Pale Ale or IPA finish will go lower (65C/149F). So it looks like you made a fermentable wort (well converted which is a good thing), and the yeast happily did their job.

All grain often gives you lower FG than extract because in making the extract, there is quite a bit of caramelization which takes a bit to get used to (I realised I used less specialty malts when doing extra, especially crystal/caramel).

I'd bump up the mash temp a bit higher next time (68C/154F) or add 5-10% crystal/caramel. I'd stick with whatever yeast you used last time so you can hone your mash process. Changing too many things at once will make it confusing to figure out what actually made the difference.

Well done though!
 
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