Author Topic: Adding sugar during fermentation  (Read 354 times)

Offline Z-man

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Adding sugar during fermentation
« on: October 19, 2020, 01:58:57 PM »
So, for some reason I ended up with a lower than expected original gravity. Making a beer that was supposed to come out to 1.086, but the hydrometer read 1.06. When i transferred to the fermenter, I left about half a gallon in the kettle (all the gross stuff at the bottom below the spigot), and I lost about 1/2  gallon during the boil (which lasted 60 minutes). I topped the fermenter off at 5 gallons with cold water.

Was this amount left in the kettle enough to drop my OG this many points? I also took my hydro reading after I pitched my yeast (maybe 30 minutes or more), so not sure if this would play a part.

Can i add some sugar to increase the ABV without ruining the beer? if so, what's a good amount?

Thanks

Offline denny

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Re: Adding sugar during fermentation
« Reply #1 on: October 19, 2020, 02:36:35 PM »
Probably mismeasurement due to topping off if you measured after you did it.
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Offline jverduin

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Re: Adding sugar during fermentation
« Reply #2 on: October 19, 2020, 02:45:55 PM »
The stuff left behind, usually called trub. Should not adversely effect your original gravity. That volume of stuff has various solids mixed with your wort, but the liquid part of it is similar to what you drained off the top.

Taking a hydrometer sample after yeast addition (but before active fermentation) should also not reduce the OG or throw it off at all. If you poured a large starter in, that can reduce the original wort’s OG - but that is something that can be calculated and shouldn’t result in a 1.020 or more reduction.

Adding sugar will raise your OG. It is about 1.009 points per pound in a 5 gallon batch. However, table sugar and corn sugar are nearly full fermentable by beer yeast. The result is that you will raise the ABV, and the beer will seemingly dry out as it will finish at the same finishing gravity as the beer before the addition. Your originally planned OG of 1.086 might have finished at an estimated 1.022 (guesstimate). Your 1.060 beer may go down to 1.014. If you add 2.5 lbs of sugar, the OG gets near 1.086, but may still finish around 1.014 because of the fermentability of sugar. Rather than worry about math, the point is that sugar does not make up for the lost OG without other impacts.

Some styles favor sugar additions (many Belgian styles and double IPAs), but there are recipes that give guidance on amounts. A single pound is often used in 5 gallons but some use more.

I would not advise adding sugar unless you are OK with the resulting impacting of higher ABV with a thinner, dry-tasting result. If you do decide to, I’d use restraint.

It’s better to figure out why the miss and dial it in better next time.


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Offline Z-man

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Re: Adding sugar during fermentation
« Reply #3 on: October 19, 2020, 03:10:55 PM »
Thanks for the response. I'm likely going to opt to not add anything and just see how it turns out rather than risk it. My guess is that the OG was off because i took a diluted sample after mixing in top off water improperly, OR my initial recipe calculations were not right since it was the first time i designed my own recipe. Another possibility is that my hydro sucks.

I get completely different OG estimates when using beersmith vs using brewers friends. I originally used BF, which gave me the 1.086 estimate, but beersmith using the same recipe gave me an estimate of 1.067, which would make my miss on OG less egregious and more acceptable, but still annoying.

Here's my recipe

Steeping grains
1 lb 2-row pale malt
.5 lb flaked oats

Boil
60 min: 6lb Pilsen LME
60 min: 2 lb Pilsen DME
60 min: 1 lb Wheat DME
60 min: 1 oz nugget
15 min: 1lb corn sugar
05 min: 2 oz citra, 1 oz mosaic

Hop stand:2 oz citra, 1 oz amarillo



Offline jverduin

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Re: Adding sugar during fermentation
« Reply #4 on: October 19, 2020, 03:24:54 PM »
The 1.086 seems close to me.
In 5 gallons, estimate:
LME about 7 pts per pound
DME about 9
Sugar 9

2-row 5 pts
Oats 5 pts

Comes out in the mid 1.080’s

I would guess that your water addition (top off) did not thoroughly mix. I think this happens easily. When using extracts, it is hard to miss the gravity since you are not dependent on extraction and efficiency rates like all-grain.

I think you your OG was probably fine but you pulled a watered down portion for your sample. Occam’s Razor... it has the least amount of assumptions attached.


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Offline Z-man

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Re: Adding sugar during fermentation
« Reply #5 on: October 19, 2020, 03:43:29 PM »
Thanks, the points values seem pretty clear. Doesn't adding water typically dilute OG? Trying to aim to not have to top off at all next time by adding more pre-boil volume to account for the losses pre-emptively. I'm losing about a half gallon for each 60 minutes of the boil, and would rather be precise in the kettle versus counting on water additions. Thanks again for the advice.

Offline rburrelli

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Re: Adding sugar during fermentation
« Reply #6 on: October 19, 2020, 04:34:48 PM »
Thanks, the points values seem pretty clear. Doesn't adding water typically dilute OG? Trying to aim to not have to top off at all next time by adding more pre-boil volume to account for the losses pre-emptively. I'm losing about a half gallon for each 60 minutes of the boil, and would rather be precise in the kettle versus counting on water additions. Thanks again for the advice.
If you are using Brewers Friend or Beersmith you would do well by looking into making a profile for your equipment. That way when you create recipes the software takes into account your specific boil off rate, absorption, efficiency, etc and adjust from there. This helps you be more accurate and consistent with your brews.
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Offline jverduin

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Re: Adding sugar during fermentation
« Reply #7 on: October 19, 2020, 05:19:27 PM »
Thanks, the points values seem pretty clear. Doesn't adding water typically dilute OG? Trying to aim to not have to top off at all next time by adding more pre-boil volume to account for the losses pre-emptively. I'm losing about a half gallon for each 60 minutes of the boil, and would rather be precise in the kettle versus counting on water additions. Thanks again for the advice.
Water does dilute the OG, but I’m guessing yours didn’t mix well with the denser wort when you topped off. I’m guessing you sampled a watery portion of the mix. It’ll churn during fermentation eventually, so you don’t need to do anything to fix it.


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Offline Z-man

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Re: Adding sugar during fermentation
« Reply #8 on: October 19, 2020, 06:47:34 PM »
Thanks for the responses! going to do an analysis of my equipment to get it set up more accurately. Would love to avoid having to top of at all in the future. Thanks all!

Offline BrewBama

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Re: Adding sugar during fermentation
« Reply #9 on: October 19, 2020, 09:04:48 PM »
Just to chime in after-the-fact, I added a lb of candi syrup three days after fermentation began on the last beer I brewed. I had to figure one OG for the brewday just for my personal satisfaction of hitting a target into the FV (without the sugar), and then a separate OG for ABV planning purposes.  Strange.


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Offline Z-man

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Re: Adding sugar during fermentation
« Reply #10 on: October 20, 2020, 03:45:05 PM »
Yeah, i still dont have a full grasp on how much sugar raises ABV but it seems like a lb of sugar is about 9 gravity points. Not sure if it matters when you add it for it to hit that value, but it does seem like sugar added after a boil dries the beer out.

Offline denny

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Re: Adding sugar during fermentation
« Reply #11 on: October 20, 2020, 03:50:20 PM »
Yeah, i still dont have a full grasp on how much sugar raises ABV but it seems like a lb of sugar is about 9 gravity points. Not sure if it matters when you add it for it to hit that value, but it does seem like sugar added after a boil dries the beer out.

As does sugar added before fermentation
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Offline jverduin

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Adding sugar during fermentation
« Reply #12 on: October 20, 2020, 04:07:39 PM »
Yeah, i still dont have a full grasp on how much sugar raises ABV but it seems like a lb of sugar is about 9 gravity points. Not sure if it matters when you add it for it to hit that value, but it does seem like sugar added after a boil dries the beer out.
I might not be thinking this one through properly, but a 9 point drop between OG and FG equates to a corresponding 1.2 addition to ABV percentage. So (I think) 1 Lb of sugar in 5 gals of wort or beer would potentially contribute a 1.2 ABV increase. (Assuming yeast are fully prepared to ferment it).


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« Last Edit: October 20, 2020, 05:35:42 PM by jverduin »

Offline Z-man

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Re: Adding sugar during fermentation
« Reply #13 on: October 20, 2020, 07:52:32 PM »
Interesting. I think that makes sense

So from 1.086 to 1.015 = .071*1.2 = 8.5% ABV (more or less) ?

Offline jverduin

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Re: Adding sugar during fermentation
« Reply #14 on: October 21, 2020, 09:53:41 AM »
Interesting. I think that makes sense

So from 1.086 to 1.015 = .071*1.2 = 8.5% ABV (more or less) ?

Not quite. The 1.2 number was associated with a 9 point drop in gravity. With a 71 point drop (1.086-1.015), there would be almost (8) 9-point drops. This roughly means 8 * 1.2 which is 9.6% abv. (This was using estimates and "abouts" - below is the more accurate calculation)

The more accurate calculation is (OG-FG)*131.25 which = .071*131.25 = 9.32%