Late fermentable addition, wrong ABV

[Doddles]

I frequently add sugar to the fermenter part way through the fermentation. I've tried using the Late Addition: Fermenter option (using the web-based Brewer's Friend). It adjusts the OG and FG fine, but the estimated ABV ends up way off (presumably because the OG is being used without taking into account the added sugar).

Is this a known bug? I saw something similar mentioned on an earlier post (ticket #1496?) but that was supposedly fixed.

Would also be great to have a "Late Addition" type of log entry.

Thanks!

 

[GFHomebrew]

I frequently add sugar to the fermenter part way through the fermentation. I've tried using the Late Addition: Fermenter option (using the web-based Brewer's Friend). It adjusts the OG and FG fine, but the estimated ABV ends up way off (presumably because the OG is being used without taking into account the added sugar).

Is this a known bug? I saw something similar mentioned on an earlier post (ticket #1496?) but that was supposedly fixed.

Would also be great to have a "Late Addition" type of log entry.

Thanks!

I know there is a late addition function in the recipie creator in fermentables that might help

 

[Doddles]

I know there is a late addition function in the recipie creator in fermentables that might help

Yep - that's what I'm using. But it doesn't seem to calculate the expected ABV correctly, given what you put in there.
For example, if I include 1kg cane sugar for a 24L batch, as a fermenter addition it only adds 0.17 to the ABV. That is entirely due to the lower FG, not the alcohol from fermentation of the extra kilogram of sugar.

 

[Pricelessbrewing]

Thanks @Doddles.

We have an existing ticket to fix this, I'm adding this forum thread to that ticket and will followup when this gets fixed. At this moment we're focusing on other issues so I don't have an ETA on a resolution at this time.

 

[Doddles]

Thanks @Doddles.

We have an existing ticket to fix this, I'm adding this forum thread to that ticket and will followup when this gets fixed. At this moment we're focusing on other issues so I don't have an ETA on a resolution at this time.

Thanks for letting me know

 

[Cajunbubba]

Yes the fix should be only to the ABV, since the OG remains the same. they should just take the OG add the sugar points and calculate the ABV from that. Using my tilt I can see about a 6-7 point increase on a 6 gallon batch. see attached graph. note OG did not change but 6-7 points were added along the way.

 

[Dexlor]

Would also be great to have a "Late Addition" type of log entry.

I second this. Had a brew day where I completely missed my pre-boil gravity so I added DME to compensate. Would be nice to have a way to track that in the brew recipe rather than updating the recipe and the efficiency. I suppose this is what snapshots are for, eh?

 

[LeakyKettle]

Any update on this? I also am using the "late fermenter addition" option to exclude late sugars from the post-boil OG, but how do I tell the software that I've actually added the sugars and they should now be part of the gravity calculation?

 

[Yooper]

Any update on this? I also am using the "late fermenter addition" option to exclude late sugars from the post-boil OG, but how do I tell the software that I've actually added the sugars and they should now be part of the gravity calculation?

That’s a tough one- since the ABV is based on OG-FG, so it would have to be added to the calculator as a late addition for that to show. But you can document all of it in the brew log when you brew the batch.

 

[Mallonee's Malt]

Late to the party but curious about this one. @Cajunbubba I'm curious about how the rest of your Tilt screenshot looked. How did the Tilt do on the ABV dial when the gravity was changed partway through.

Well, thinking about it, the Tilt just reports specific gravity. That chart is also a part of the BrewersFriend calculation. So not only does the recipe ABV need to be updated with the late addition option, but the Tilt streaming also needs to be updated. I've never really used brew log but that would be the obvious place to document an addition in the form that the calculations could use.

 

[Donoroto]

Late to the party but curious about this one. @Cajunbubba I'm curious about how the rest of your Tilt screenshot looked. How did the Tilt do on the ABV dial when the gravity was changed partway through.

Well, thinking about it, the Tilt just reports specific gravity. That chart is also a part of the BrewersFriend calculation. So not only does the recipe ABV need to be updated with the late addition option, but the Tilt streaming also needs to be updated. I've never really used brew log but that would be the obvious place to document an addition in the form that the calculations could use.

I haven’t seen him on the forum in a few minths, so don’t be surprised if there’s no answer.

I use the Tilt, and it does report specific gravity, then calculated an abv based in the first sg reading it has. Which would ignore any sugar additions. Of course, one can manually manipulate the spreadsheet on Google Docs, simply setting the first specific gravity reading to the highest reading you have, but the highest reading might not be as high as it would’ve gotten if you added the sugar before fermentation, I guess.

 

[Mallonee's Malt]

I use the Tilt pretty blindly to calculate ABV and see FG. In a "regular" fermentation the ABV depends entirely on the first OG reading. I've dropped the Tilt into the bucket while the wort is still warm and the SG will change by a few points by the time I pitch yeast. I usually edit out the pre-pitch readings since that gives me a lower (and incorrect) ABV.

I did answer my own question in the previous post after I thought about it.

But if BrewersFriend is going to support the concept of "fermenter late addition" then the recipe should account for it in total ABV, but also provide correct post mash and post boil gravity numbers (so we can check and calculate our efficiency) but then have the Tilt correctly account for the sugar adds. That means that the "OG" can't blindly be the beginning total of the calculation. I can see that it would require putting the late addition in the brew log, but once there the Tilt streaming log should account for it. I don't know if there needs to be an "OG" reading for the starting gravity and then a "TG" for total gravity or something like that.

I've really only looked at this concept for brewing fairly "large" beers. It's nice to give the yeasties a chance to work on the malt sugar before just throwing corn sugar or brown sugar at them.

 

[Craigerrr]

I've really only looked at this concept for brewing fairly "large" beers. It's nice to give the yeasties a chance to work on the malt sugar before just throwing corn sugar or brown sugar at ththem.

Is this an actual "brewing thing" adding fermentable sugar to the fermenter mid ferment?
I just wonder what the difference would be, is there any science related to this?

 

[BarbarianBrewer]

I have heard of adding an additional yeast after fermentation has begun, but not sugar or malt. However, I could see a benefit in that the yeast would be less stressed if they don't have to start in a very high sugar density environment. Once the yeast have established themselves and are working hard, you give them more sugars to work on. However, would introducing a bunch of additional sugars after the yeast's growth phase has ended cause any yeast stress? I don't know...just thinking out loud here.

Edit: I'm only referring to very high gravity beers (1.1+ sg). I don't see any benefit for a normal gravity beer.

 

[Mont Y. Märzen]

That’s a tough one- since the ABV is based on OG-FG, so it would have to be added to the calculator as a late addition for that to show. But you can document all of it in the brew log when you brew the batch.

I would expect that a new 'post-boil' gravity would be in order for determining efficiency, but the OG would indeed change since new fermentables were introduced post-boil.

This could perhaps tie-in with bottle conditioning which adds to ABV. Currently, I have to calculate that separately and just know I'm that much higher than the recipe shows. (as much as 0.5% on a 3+vols carbination for a Belgian style)

Along these lines, one of my buddies added Koji to the fermenter of a Toasted Rice Ale. We're pretty sure there was additional sugars added, but unsure how much. The beer finished at 1.000. (we're not even sure how to calculate OG for Sake yet...)

 

[Mont Y. Märzen]

Is this an actual "brewing thing" adding fermentable sugar to the fermenter mid ferment?
I just wonder what the difference would be, is there any science related to this?

I used to add honey, but now I wait until I keg it, precisely to hold off fermenting it. I guess even then, as with a late fruit addition, the ABV will increase over time depending on how the beer is held after the addition. I've never heard of boosting ABV post boil in the fermenter though.

And I don't know if this is related, but Lactose messes with sg when added to the boil/whirlpool. The hydrometer reads higher, but the sugars aren't fermentable. We have to do side-math and a Fast Ferment Test to determine target FG and expected attenuation.

 

[Yooper]

I used to add honey, but now I wait until I keg it, precisely to hold off fermenting it. I guess even then, as with a late fruit addition, the ABV will increase over time depending on how the beer is held after the addition. I've never heard of boosting ABV post boil in the fermenter though.

And I don't know if this is related, but Lactose messes with sg when added to the boil/whirlpool. The hydrometer reads higher, but the sugars aren't fermentable. We have to do side-math and a Fast Ferment Test to determine target FG and expected attenuation.

Even though the sugars aren't fermentable, it does increase the OG. Whatever points are added by the lactose, those SG points will be left after fermentation. What I mean is, if the lactose adds .008 SG points, it will still be .008 Fg points higher.

 

[Mont Y. Märzen]

Even though the sugars aren't fermentable, it does increase the OG. Whatever points are added by the lactose, those SG points will be left after fermentation. What I mean is, if the lactose adds .008 SG points, it will still be .008 Fg points higher.

Yeah, but something is still off. Even doing that math no batch ever comes out right. It is almost like the lactose is inhibiting maltose fermentation. I may try comparing by using a refractometer and see if those numbers are more sane. That is a better approximation of fermentable sugars than SG in this case anyway.