Refractometer correction with sugar additions during ferment.

[hungupdown]

Doing a brew where sugar has to be added as ferment progresses, and wondering if anyone knows a good way to find the corrected FG(SG) from brix ?

Brew is a strong imperial stout, Target 14.3% ABV, post boil gravity 1130. Up to 2kg dextrose is gradually added as ferment progresses, that's up to around 5% of the alcohol. This is so yeast is not stressed by an extreme OG, and you can quit additions if fermentation stalls, before reaching 14.3% (rather than ending with something far too sweet).

I normally use the brewersfriend calculator, that takes figures for OG brix, and FG brix, to give the corrected FG(SG) & ABV, but don't think it will give valid results directly, where sugar is added between the readings entered.

Can the calculator be made to work, by increasing the OG entered, by the SG change the added amount of sugar would give?
eg:

OG - (Brix WRI): 31.4 ; Wort Correction Factor: 1.04 ; OG - Corrected 1.130

2 days: brix 17.6% ; Wort Correction Factor: 1.04 ; FG - Corrected 1.035 ; ABV 11.86% ☆
Dextrose addition 185g ; Fermentation volume 20L ;
Dissolved sugar 9.25 (g/L) ; would give Specific Gravity 1.00362 (or 3.6 gravity points, round up to 4). Vinolab gravity-density-sugar converter

Then putting OG 1.130 + .004 = 1.134
 5 days: brix 17.5% ; Wort Correction Factor: 1.04 ; FG - Corrected 1.034 ; ABV 12.40%

A hydrometer reading on day 5, was close at 1.035 (inc. temperature correction), so looks promising.

The second sugar addition, 200g, is now in.
So for my next readings, I'd calculate for the total added dextrose 385g; 19.25(g/L) ; SG 1007.47 (or 7 SG points) ; OG =1.130+.007 =1.137

☆ At high alcohol levels, an uncorrected brix conversion is way off: 2 days, brix 17.6% : uncorrected conversion SG=1.072 (Vinolab); vs 1.035 corrected (brewersfriend).

 

[DuncB]

I remember asking about this a while ago for my imperial stout.
Just take your OG but add the dextrose that is chaptalised in as a beginning ingredient to the software. This will give you a higher OG and use that figure as your original OG in the refractometer conversion part of brewfather.
You could add the PPG for your dextrose addition to your OG if you want to do some non software calculations. Then use that figure as your OG.
My stout was 1.107 and I added 2kg of dextrose and used WLP 099. It coped fine with the alcohol level.
Must try it as it's been in the keg maturing for 14 months.

 

[pocketmon]

Check this:

http://www.woodlandbrew.com/2013/02/abv-without-og.html

 

[IslandLizard]

Don't forget to add nutrients along with your sugar additions.

 

[DuncB]

Check this:

http://www.woodlandbrew.com/2013/02/abv-without-og.html

Yes, if you have both a refrac, and a hydro. when it's done, measure it with both, then use a calc to eduguess the OG and ABV....(so far for me it's been pretty spot on)

quote was from the final post in this thread.
https://www.homebrewtalk.com/threads/gravity.702841/#post-9318627
Shame he took the secret with him.

 

[DuncB]

There are formulae for this. They are a sort of estimates on top of estimates kind of thing. Here's one:
https://www.vinolab.hr/calculator/alcohol-from-hydrometer-refractometer-en27
But in your case, if you knew the OG of the stout without the sugar, you could pop that into the FruitCalc spreadsheet, along with your Sugar Addition (select "Corn Sugar" from the "fruit" dropdown) and get a calculated effective combined OG.

FruitCalc Download

Found it thanks @VikeMan new it was somewhere

 

[hungupdown]

Don't forget to add nutrients along with your sugar additions.

Sounds an idea worth trying.
Did add yeast nutrient at start, then had Krausen up to lids - 20L batch split 10L in 2x 30L buckets.
But has been seeming a bit slow for last few days, (now at day 8), despite upping the temperature. So off for a teaspoon of DAP nutrient now.

 

[hungupdown]

Found it thanks @VikeMan new it was somewhere

FruitCalc

- doesn't seem to have any fields for entry of Brix readings?

 

[hungupdown]

I remember asking about this a while ago for my imperial stout.
Just take your OG but add the dextrose that is chaptalised in as a beginning ingredient to the software. This will give you a higher OG and use that figure as your original OG in the refractometer conversion part of brewfather.
You could add the PPG for your dextrose addition to your OG if you want to do some non software calculations. Then use that figure as your OG.
My stout was 1.107 and I added 2kg of dextrose and used WLP 099. It coped fine with the alcohol level.
Must try it as it's been in the keg maturing for 14 months.

Thanks, I'd not spotted that option in Brewfather.
Had clicked on Refractometer tool, but not seeing box for OG, thought it wasn't suitable. But, once the 'fermented wort' checkbox is selected, OG appears.

It produces figures, exactly matching those from brewersfriend. Guess formulae is more likely to be right, when two sites use the same.

What FG/ABV did the WLP099 get to?

I'm using Nottingham, 6 day slurry from a small beer (4.0% ABV).
Stout is a partial mash recipe, with 3kg of LME added at end of boil (taking OG from 1091 to 1136). Today, after 385g dextrose, it's at ABV 12.8%; SG 1032.
Strips of whisky barrel staves for aging, now soaking in a little fresh whisky. Hardest part, will be leaving it alone, for 12 months or more.

 

[hungupdown]

If anyone can point me to the formula for Brix-OG -> Brix-FG, I could do a spreadsheet for including post ferment sugar additions.

 

[IslandLizard]

So off for a teaspoon of DAP nutrient now.

Don't overdo the nutrients, you don't want to taste them. A little goes a long way.
Pre-dissolve the sugar and nutrients before adding to the batch. A medium thick syrup, just being pourable, a little thicker than maple syrup, is a good middle ground between adding the most sugar and the least amount of water, resulting in the highest gravity increase.

IIRC, 1/2 tsp of mixed nutrients per 5 gallons of beer should be enough when adding alcohol boosting sugars during fermentation. Using a mix of nutrients is better than a single source, such as DAP only.

Once you get into the higher gravity/alcohol regions, starting to push the limits of your yeast, it's better to spread the total amount of sugar over multiple smaller additions (slow feeding), together with a proportionally smaller amount of mixed nutrients.

When you start pushing the yeast's limits it's advised to take a gravity reading each time before adding more sugar, to confirm your yeast is still working. Once she has stopped attenuating the last sugar addition, she's done, and you've reached the gravity/alcohol limit for that batch.

There are articles about all this.

 

[DuncB]

If anyone can point me to the formula for Brix-OG -> Brix-FG, I could do a spreadsheet for including post ferment sugar additions.

https://brewingcalculators.com/degrees-brix-to-specific-gravity/Then read the reference at the end of it.

 

[hungupdown]

https://brewingcalculators.com/degrees-brix-to-specific-gravity/Then read the reference at the end of it.

Looked, but only calculates unfermented wort. And finishes saying "use a hydrometer to take a direct density measurement once fermentation begins".

 

[hungupdown]

Don't overdo the nutrients, you don't want to taste them. A little goes a long way.
Pre-dissolve the sugar and nutrients before adding to the batch. A medium thick syrup, just being pourable, a little thicker than maple syrup, is a good middle ground between adding the most sugar and the least amount of water, resulting in the highest gravity increase.

IIRC, 1/2 tsp of mixed nutrients per 5 gallons of beer should be enough when adding alcohol boosting sugars during fermentation. Using a mix of nutrients is better than a single source, such as DAP only.

Once you get into the higher gravity/alcohol regions, starting to push the limits of your yeast, it's better to spread the total amount of sugar over multiple smaller additions (slow feeding), together with a proportionally smaller amount of mixed nutrients.

When you start pushing the yeast's limits it's advised to take a gravity reading each time before adding more sugar, to confirm your yeast is still working. Once she has stopped attenuating the last sugar addition, she's done, and you've reached the gravity/alcohol limit for that batch.

There are articles about all this.

Only have DAP. It suggests 1 level tsp per gallon.
I'd added 3 level tsp, at start, and now 1 more with 3rd sugar addition.

Ferment seemed really slow, stuck around SG 1032. But erupted (3 inches foam) on adding 100g dextrose, so upped addition to 200g.
Guess yeast might have already finished using the fermentable sugars, though target FG was 1018.
Alcohol from 2kg fermented dextrose, would maybe decrease FG by 5 SG points.

Some places suggest (for very high ABV), adding all additonal dextrose once Krausen has died down. Others, say the yeast will convert simple sugars first, so it's best not to add these till complex sugars have been used.

So not sure if I should try waiting (weeks) to let complex sugars convert, before adding remaining dextrose.

 

[IslandLizard]

Only have DAP. It suggests 1 level tsp per gallon.

No-no-nooooo!
That's for wine...

 

[IslandLizard]

Ferment seemed really slow, stuck around SG 1032.

Is that measured with a refractometer? And corrected using Brewer's Friend's Refractometer calculator, using Part II (alcohol present)?

 

[hungupdown]

Is that measured with a refractometer? And corrected using Brewer's Friend's Refractometer calculator, using Part II (alcohol present)?

Yes refractometer, and yes Brewers friend (it's calculations match brewfather tool - refractometer/Brix - fermented wort results).

Today had reached corrected OG 1143; Brix 17.1%; corrected FG 1026; ABV 14.5%. Tried adding another 200g of dextrose, but after 100g stirred in, the 20l turned into 15L, with 15L foam head (not sure if it's Krausen at this stage).
Remaining 100g went in 2 hours later. Tasting lovely (to me) at this stage.
Think Nott yeast must like the taste of DAP, added to the trub off 23L small beer. Possibly no DAP needed, where starter volume was bigger than the brew.

 

[IslandLizard]

Tried adding another 200g of dextrose, but after 100g stirred in, the 20l turned into 15L, with 15L foam head

Undissolved dextrose?
That would create nucleation sites, onto which the dissolved CO2 forms bubbles, creating much foam...
Stirring your CO2-rich beer does something similar.

 

[DuncB]

No need to stir it in, although it falls to bottom of fermenter it dissolves. I watched this when I chaptalised my imperial stout with dextrose.

 

[hungupdown]

When you start pushing the yeast's limits it's advised to take a gravity reading each time before adding more sugar, to confirm your yeast is still working. Once she has stopped attenuating the last sugar addition, she's done, and you've reached the gravity/alcohol limit for that batch.

Seems yeast is still hungry, as still getting massive foam at last dextrose addition, and following gravity was lower each time. But having now exceeded desired ABV (target 14.5, now at 15%) don't want to push it to far, then find bottles won't carbonate.

I often see a (slightly lesser) explosion of CO2 foam, when adding sugar to wine that has fermented past the required gravity.
This foaming, will still happen after mixing in stabilisers (sorbate + sulphites) to stop fermentation. So believe this rapid reaction is from enzymes the yeast has already created. Think I'd read about that somewhere, but can't find it now.

Now wondendering how long it's best left in secondary, for the least to clean up, before priming & bottling/kegging, for 12 - 28 months on cask oak.

 

[DuncB]

A new pitch of yeast or a sprinkle of dry yeast in each bottle with priming sugar will help to ensure carbonation occurs.
What remains after resting in oak barrel for a few months at high alcohol not likely to kick into life at bottling.

 

[VikeMan]

FruitCalc View attachment 839959- doesn't seem to have any fields for entry of Brix readings?

I suggested FruitCalc because you can use it to get the effective combined OG, given your base beer's OG and your sugar addition. Fruitcalc uses specific gravity, not refractometer brix readings. But you can convert your original refractometer reading to specific gravity using a refractometer calculator, like I think you did in post #1, i.e. 1.130. Enter that in Fruitcalc, along with your batch size, and then enter the sugar addition(s) on one of the "Fruit" rows. Your effective combined OG will be shown in the result.

Then, if you want to keep using your refractometer, you can enter (trial and error, but it won't take long) brix readings in the "OG" brix in the calculator until the OG in that calculator is showing the same gravity that fruitcalc gave you as the combined effective OG. The brix you entered to hit that is your combined effective "OG" brix.

 

[hungupdown]

A new pitch of yeast or a sprinkle of dry yeast in each bottle with priming sugar will help to ensure carbonation occurs.
What remains after resting in oak barrel for a few months at high alcohol not likely to kick into life at bottling.

Thanks. Was wondering if I'd need a CBC yeast, or if the enzymes? remaining (that are now making foam at sugar additions), would persist.

Also, wasn't sure if botteling yeasts, might starting fermenting dextrins etc. At 15% ABV, the choice of CBC yeast will be limited.

 

[Hoochin'Fool]

EC-1118 can go up to 18% abv, and it's significantly cheaper than CBC-1... I've been using it to bottle everything over 10% abv.

https://www.homebrewtalk.com/thread...l-recipe-a-few-weeks-ago.703564/post-10328416

 

[mac_1103]

wasn't sure if botteling yeasts, might starting fermenting dextrins etc.

Bottling yeasts only ferment simple sugars. Wine yeasts can't ferment maltose, much less dextrins.

 

[hungupdown]

Check this:

http://www.woodlandbrew.com/2013/02/abv-without-og.html

Thanks for the suggestion. Then found tool on Vinolab.

The woodlandbrew tables, only go up to FG refractometer reading of 12, but my imperial stout is 17.5. Site does give formula used, so have option to calculate yourself.
But Vinolab - Alcohol from Hydrometer & Refractometer tool does it for you. Though it came up with z slightly higher ABV figure (by 0.5%) than a woodlandbrew table entry tried.

Out of interest I've tried getting final ABV in three ways:

1) from refractometer readings
initial Brix 31%
corrected OG 1128 (using wort correction factor 1.04)
effective OG 1149 with sugar additions 1.1kg in 20L (adds 21 gravity points)
final Brix 17.5%
gives corrected FG 1026; ABV 15.2%

2) from Hydrometer readings (temperature corrected)
initial OG 1134
effective OG 1155 with sugar additions (+21 gravity points)
FG 1011
ABV 18.9%

3) from final refractometer and Hydrometer readings
final Brix 17.5%
FG 1011
ABV 22.75% (using Vinolab tool)

The recipe in Brewfather was OG 1127; 1.2 kg dextrose addions FG 1018; ABV 14.3%
Hydrometer OG was 1134, so 7 above target, but that's about balanced by reduction of dextrose to 1.1kg
FG was 7 below target, so that's about an additional 1% ABV, or 15.5% total.

Method 3, seems suspect. Maybe should try it with some commercial beer.

 

[hungupdown]

Just take your OG but add the dextrose that is chaptalised in as a beginning ingredient to the software. This will give you a higher OG and use that figure as your original OG in the refractometer conversion part of brewfather.

Guess, with my initial gravity being slightly above target, I'd first need to play with efficiency setting (to get matching predicted gravity), then move the sugar addition to the start ingredients.

 

[DuncB]

Guess, with my initial gravity being slightly above target, I'd first need to play with efficiency setting (to get matching predicted gravity), then move the sugar addition to the start ingredients.

Just use your measured OG as the figure in brewfather and then add the sugar as further ingredient.
Is the mash.

 

[pocketmon]

Thanks for the suggestion. Then found tool on Vinolab.

The woodlandbrew tables, only go up to FG refractometer reading of 12, but my imperial stout is 17.5. Site does give formula used, so have option to calculate yourself.
But Vinolab - Alcohol from Hydrometer & Refractometer tool does it for you. Though it came up with z slightly higher ABV figure (by 0.5%) than a woodlandbrew table entry tried.

Out of interest I've tried getting final ABV in three ways:

1) from refractometer readings
initial Brix 31%
corrected OG 1128 (using wort correction factor 1.04)
effective OG 1149 with sugar additions 1.1kg in 20L (adds 21 gravity points)
final Brix 17.5%
gives corrected FG 1026; ABV 15.2%

2) from Hydrometer readings (temperature corrected)
initial OG 1134
effective OG 1155 with sugar additions (+21 gravity points)
FG 1011
ABV 18.9%

3) from final refractometer and Hydrometer readings
final Brix 17.5%
FG 1011
ABV 22.75% (using Vinolab tool)

The recipe in Brewfather was OG 1127; 1.2 kg dextrose addions FG 1018; ABV 14.3%
Hydrometer OG was 1134, so 7 above target, but that's about balanced by reduction of dextrose to 1.1kg
FG was 7 below target, so that's about an additional 1% ABV, or 15.5% total.

Method 3, seems suspect. Maybe should try it with some commercial beer.

With so high ABV, the formula commonly used is not precise enough.

Watch this for explanation,


By his corrected formula, I got 22.5% ABV from 1155 to 1011 instead of 18.9%.
22.5% is close to your method 3.

 

[hungupdown]

With so high ABV, the formula commonly used is not precise enough.

Watch this for explanation,


By his corrected formula, I got 22.5% ABV from 1155 to 1011 instead of 18.9%.
22.5% is close to your method 3.

Very interesting explanation, and rhanks for doing the calculation.

I wonder if ethanol effect on volume, would affect the final Brix readings by the same amount?