Final Gravity Misses High

[Toddsgate]

I am still learning quite a bit, that's a given as I'm only 5 batches of BIAB into brewing. I also have several Mr Beer brews under my belt, though they really only helped me while learning terminology. With that said, let me break down the scenario for my latest batch, including my recipe link, and hopefully you can help me in my quest. Every batch I have brewed has been for 2-1/2 gallons.

I developed the following Irish Red Ale recipe after searching several other recipes here on BF as well as other websites.
https://www.brewersfriend.com/homebrew/recipe/view/1528312/bonham-buckley-s-irish-red

The equipment I currently use is very basic:

5 gallon aluminum brew kettle
Ice bath
5 gallon brew bucket with bubbler airlock
Auto Siphon 1/2" racking cane
5 gallon bottling bucket with spigot

Strike water was heated to 162.5* F prior to submerging bag and grains. Temp dropped and maintained at about 156* F for 1 hour.
Pre-boil gravity was recorded at 1.032 (1.031 expected)
All water/wort volumes were reached or within specs before and after boil
Original Gravity recorded at 1.047 (1.046 expected)
After cooling in ice bath, the wort was transferred through a sanitized mesh strainer into the 5 gal fermenter
Wort temp was around 65* F when I pitched 1 package of Safale S-04
All sanitation practices were followed.
All temperatures were verified with 2 or 3 different thermometers.
At 10 days, I took a gravity reading with 2 separate hydrometers recording 1.016
At 14 days the FG was recorded as 1.015 (1.010 expected)
Fermentation temps in the closet ranged from 69-73* F

These are similar results from the 4 previous batches (2 blonde ales, 1 amber ale, 1 brown ale), though not exact. My main problem is hitting the FG within a couple of points instead of the 5 or 6 points high my batches have been.
I am leaning on it being 2 possible problems. Number 1; strike temps too high in the beginning. Number 2; too much headroom in a bucket utilized for 5 gallon batches. The bubbling of fermentation became visible within the first 24 hours.

All questions and answers are greatly appreciated!

Todd

 

[J A]

First thing that jumps out is mash temp. Fermentable sugars are produced in temp ranges from 148 to 152 when single infusion is used. At 156 you produced sugars but a lot of it would be in the form of dextrins which will not ferment out but will contribute to a higher final gravity.

In terms of fermentation, the dry yeast is usually pretty good on its own without extra nutritive supplements but it does need some oxygenation. Slosh your bucket or carboy to introduce oxygen into the wort so that there's a foamy head when you pitch the yeast. That usually helps. Also, S-04 can stall a little and is also not noted for particularly high attenuation percentage. You got around 70% attenuation which is a little low but not a total surprise. Next time, swirl the fermenter and rouse the yeast and be sure that the temp stays in the 72 degree range - fluctuating temps, especially 10 degree shifts - can cause the yeast to slow down and start to drop out and become inactive.

 

[Minbari]

Mash temp was a bit high. Leads to more unfermentable sugars, that is why it finished higher would be my guess

 

[Megary]

Also agree about Mash temp. On your next brew day, try mashing in at 156-157 and holding 150 for an hour. See what kind of attenuation you get then. If it’s still low, then we can start digging deeper. But one variable at a time. Good luck!

 

[Toddsgate]

Also agree about Mash temp. On your next brew day, try mashing in at 156-157 and holding 150 for an hour. See what kind of attenuation you get then. If it’s still low, then we can start digging deeper. But one variable at a time. Good luck

Thanks for al the above replies!

I will be brewing this exact recipe in a couple of weeks and will certainly lower my mash temperature. I have been curious, though, if fermenting 2-1/2 gal of wort in a 5-6 gal fermenter would cause any trouble. I'm pretty sure the CO2 fills the entire space as oxygen bubbles out....but thought I would ask the gurus of BrewersFriend if this could cause any trouble at all.

Todd

 

[Dave Y]

Fermentable sugars are produced in temp ranges from 148 to 152 when single infusion is used. At 156 you produced sugars but a lot of it would be in the form of dextrins which will not ferment out but will contribute to a higher final gravity.

The first thought I had was city water. Or water with a lot of chemicals in it. @Toddsgate, what is your water source - pH and do you have a water report? What, if any chemicals did you add to mash water?

These are similar results from the 4 previous batches (2 blonde ales, 1 amber ale, 1 brown ale), though not exact. My main problem is hitting the FG within a couple of points instead of the 5 or 6 points high my batches have been.

So you have a consistent result now. What is the common denominator? Thinking back on each of these brews, what was done the same process wise?


I had this issue at a previous house, brewed a batch with store bought spring water and- boom. full attenuation.
I just did a 70 Shilling ale mashed at 158F for about 75 minutes, mashed out at 170 and finished at 1.011.

 

[Toddsgate]

The first thought I had was city water. Or water with a lot of chemicals in it. @Toddsgate, what is your water source - pH and do you have a water report? What, if any chemicals did you add to mash water?

So you have a consistent result now. What is the common denominator? Thinking back on each of these brews, what was done the same process wise?


I had this issue at a previous house, brewed a batch with store bought spring water and- boom. full attenuation.
I just did a 70 Shilling ale mashed at 158F for about 75 minutes, mashed out at 170 and finished at 1.011.

Good call, and I would not use my local water with all of the limestone and flouride, etc. I have been using Ozarka Natural Spring Water. I have not had that water tested and have not added any other chemicals. I appreciate your response!

 

[Megary]

Thanks for al the above replies!

I will be brewing this exact recipe in a couple of weeks and will certainly lower my mash temperature. I have been curious, though, if fermenting 2-1/2 gal of wort in a 5-6 gal fermenter would cause any trouble. I'm pretty sure the CO2 fills the entire space as oxygen bubbles out....but thought I would ask the gurus of BrewersFriend if this could cause any trouble at all.

Todd

I don’t see this as an issue at all. Others may feel differently.

 

[Donoroto]

I have been curious, though, if fermenting 2-1/2 gal of wort in a 5-6 gal fermenter would cause any trouble. I'm pretty sure the CO2 fills the entire space as oxygen bubbles out....but thought I would ask the gurus of BrewersFriend if this could cause any trouble at all.

Todd

Nope, not a concern fermenting 2-1/2 gallons jn a 5 gallon fermenter. None whatsoever.

 

[Brew Cat]

personally I would have no problems with a Irish red stopping at .015 but yeah its your mash temperature
do what JA said if you want it lower

 

[Brew Cat]

https://byo.com/articles/irish-red-ale/

here is a nice article on the style by Gordon Strong

 

[J A]

personally I would have no problems with a Irish red stopping at .015 but yeah its your mash temperature
do what JA said if you want it lower

I've done my UK Golden Ale with S-04 and it tends to finish a little high. I just did a batch with Nottingham strain (Apex Sherwood) and it pushed lower. It's not a bad beer at all if it stays in the low teens but I like it better when it gets to 11 or lower. The last batch went to 1.010 and is crisp and clean-finishing.

Interesting note about fermentables...I did a split batch with the same wort and added Dark LME and some steeped Chocolate malt for color and flavor (Irish Red). The darker beer finished a couple of points higher. Same OG, fermentation and everything but the overall sugars available in the darker wort were not as fermentable because of the roasted malt and the LME. The difference in attenuation was 81% compared to 77% - both quite acceptable and both good beers for style but it points to the difference in the quality of the sugars we're converting during mash.

 

[Craigerrr]

I agree with all of above advice.
Lower your mash temperature.
Your fermenter size is also of no consequence.

The only thing I disagree with @J A on is the need to oxygenate your wort when using Fermentis S-04. There is no need for this, unless you are brewing high OG brews, like over 1.060.
I'm not making this up, this comes from a presentation put on by the North American Rep for Fermentis at local home brew club meeting. Since that meeting I have routinely pitched dry yeast, and not just Fermentis brand into wort up to 1.063.

The other thing that you don't need to do is rehydrate dry yeast, they don't even put those instructions for that on the packets anymore.

 

[J A]

The only thing I disagree with @J A on is the need to oxygenate your wort when using Fermentis S-04.

I don't feel strongly enough on the subject to press the point but it's the sort of thing that might make a bit of difference. I can go either way for the most part.
In my experience, when I make an effort to provide some oxygen, either pure O2 or just sloshing a lot I seem to get better attenuation and sometimes quicker fermentation and when I've skipped it, the results are slightly less robust. I haven't been in any way scientific about comparing the methods. I think it's more of a minor variable when using dry yeast.
I have given up rehydrating, though it's a hard habit to break.

 

[Zambi]

How did you measure your final gravity?
Did you correct your value for the presence of alcohol in case you used a refractometer?