FG too high

[McElvis]

I've been brewing for a while, probably 60-70 batches, and for some reason my beers haven't been finishing lately. I'm lucky to get down to 1.020.
I'm an all grain brewer using a RIMS system and fly sparging. I usually get around 75% mash efficiency and roughly the same brew-house efficiency.
I use Beersmith, crush my own grains, have a temperature regulated fermentation chamber. What else...usually use liquid yeast with a starter on a stir plate, but even with re-hydrated US-05 I've not been able to get beer down to where it's supposed to be.
The only real change I've made in the last year or so is I've gone up to 10 gal batches. I have a 60L Speidel fermenter.
I also recently got a cheap RO filter and have been working on my water profiles, nothing too crazy.
I make IPAs, Brown Ales, Stouts, Rye-PAs, and lots of Belgian beers. Not into Sours or wild Ales so much.
Grain bill is usually pretty basic.
Any thoughts?

 

[VikeMan]

You didn't happen to switch from a hydrometer to a refractometer, did you?

 

[Vale71]

Do you measure with a refractometer or a hydrometer?

 

[myndflyte]

The only thing I can think of is bad thermometer so you're getting a high mash temp, or refractometer.

 

[McElvis]

I use my refractometer pre fermentation, but a hydrometer after. I calculate the refractometer with distilled water every so often.

I'm thinking that maybe my mash PH could be part of the issue. I use acidulated malt and my ph meter's probe went out. I just got a new one before this last batch. It showed that my mash ph was at 5.15 and the run off got down to 3.3 This was the first time I have taken the run off ph.

 

[VikeMan]

I'm thinking that maybe my mash PH could be part of the issue. I use acidulated malt and my ph meter's probe went out. I just got a new one before this last batch. It showed that my mash ph was at 5.15 and the run off got down to 3.3 This was the first time I have taken the run off ph.

Sparge water would have to be heavily acidified for runoff to get down to 3.3. I mean, the sparge water itself would have to have a pH that's lower than 3.3. I think that reading is suspect.

 

[McElvis]

I thought it was low as well. I think I added lactic acid to the sparge water, I'll have to look at my notes.
The thing is, I did'nt add anything to the sparge on the last couple of beers and still had high FG.

 

[NTexBrewer]

Check your thermometer

do you oxygenate?

 

[brownni5]

We have all the information needed to diagnose your problem except for the important stuff. What's mash temp? What's OG? What's your yeast? What's your expected AA? Besides "basic," what's your grain bill like? Lots of crystal?

Something has changed. Attenuation doesn't just suddenly get crappy.

 

[Antzrhere]

I have read that if the beer going into your FV is too acidic this can (with atleast one strain) reduce the attenuation. How you get runoff at pH 3.3 is quite amazing as even mostly spent grain would offer some buffering. Have you ever checked what your post boil (pre ferment) pH is?

 

[McElvis]

We have all the information needed to diagnose your problem except for the important stuff. What's mash temp? What's OG? What's your yeast? What's your expected AA? Besides "basic," what's your grain bill like? Lots of crystal?

Something has changed. Attenuation doesn't just suddenly get crappy.

This last beer is a 10 gallon batch of Rye-PA that came in at OG:1.072
Mash temp was 154
I used 3 packs of US-05 (re-hydrated as per instructions)
Estimated attenuation was 74.7% I got 59.7%
Estimated FG was 1.017 and after 20 days I'm at 1.028 and have been there for a week.
Started at 67 deg and slowly got to 71.
Grain bill : 8.8# Viking 2 row, 8.8#IDA Pils, 5# white wheat, 1.75# Breiss 2 row, 5# flaked rye, 1# acid malt
I know the grain bill is all over the place, with the lock down I'm trying to use up what I have on hand. Some of the malt might have been a little old, but everything tasted good and I keep it in air tight containers.
Water was RO adjusted through Beersmith to match "light and hoppy".

 

[McElvis]

I have read that if the beer going into your FV is too acidic this can (with atleast one strain) reduce the attenuation. How you get runoff at pH 3.3 is quite amazing as even mostly spent grain would offer some buffering. Have you ever checked what your post boil (pre ferment) pH is?

ph of my sparge water was 6.6 and I added 2ml of lactic acid to get it down to 3.3. I didn't mean to get it that low.

 

[McElvis]

Check your thermometer

do you oxygenate?

Yes usually one min of pure 02 through a stone.

 

[VikeMan]

ph of my sparge water was 6.6 and I added 2ml of lactic acid to get it down to 3.3. I didn't mean to get it that low.

RO water has essentially no alkalinity. There's no reason to add any acid to it when using it to sparge.

 

[McElvis]

RO water has essentially no alkalinity. There's no reason to add any acid to it when using it to sparge.

That's the first time I ever had. I had never even taken the ph reading of my sparge water before. I did add "salts" to the sparge as per Beersmith.

 

[Antzrhere]

That's the first time I ever had. I had never even taken the ph reading of my sparge water before. I did add "salts" to the sparge as per Beersmith.

RO water is neutral in theory. Even if the pH decreases with temperature, the hydroxide and hydrogen availability are equal. In the real world RO water will show as acidic around pH 5ish with a pH meter as atmospheric CO2 dissolves in the water rapidly creating carbonic acid, but this is a very weak acid that has little or no ability to buffer anything. Salts may change pH slightly (but not a great deal), but this depends on whether the salt is from a strong/weak acid/base.

 

[brownni5]

This last beer is a 10 gallon batch of Rye-PA that came in at OG:1.072
Mash temp was 154
I used 3 packs of US-05 (re-hydrated as per instructions)
Estimated attenuation was 74.7% I got 59.7%
Estimated FG was 1.017 and after 20 days I'm at 1.028 and have been there for a week.
Started at 67 deg and slowly got to 71.
Grain bill : 8.8# Viking 2 row, 8.8#IDA Pils, 5# white wheat, 1.75# Breiss 2 row, 5# flaked rye, 1# acid malt
I know the grain bill is all over the place, with the lock down I'm trying to use up what I have on hand. Some of the malt might have been a little old, but everything tasted good and I keep it in air tight containers.
Water was RO adjusted through Beersmith to match "light and hoppy".

Looks like a breakdown in process somewhere not listed, something like an incorrect temp reading or something. The above looks ok to me.

 

[TheMadKing]

This last beer is a 10 gallon batch of Rye-PA that came in at OG:1.072
Mash temp was 154
I used 3 packs of US-05 (re-hydrated as per instructions)
Estimated attenuation was 74.7% I got 59.7%
Estimated FG was 1.017 and after 20 days I'm at 1.028 and have been there for a week.
Started at 67 deg and slowly got to 71.
Grain bill : 8.8# Viking 2 row, 8.8#IDA Pils, 5# white wheat, 1.75# Breiss 2 row, 5# flaked rye, 1# acid malt
I know the grain bill is all over the place, with the lock down I'm trying to use up what I have on hand. Some of the malt might have been a little old, but everything tasted good and I keep it in air tight containers.
Water was RO adjusted through Beersmith to match "light and hoppy".

I suspect your mash temp/RIMS overheating your mash to keep the 10 gallons at temp.

You switched to 10 gallon batches, so where are you measuring your mash temp for driving your RIMS heater? If you are getting poor mixing through a larger mash, you might be overheating large portions of your mash, or overheating what's in your RIMS tube compared to your bulk mash temp