# Advice for calculating bottle priming sugar for partially-carbonated beer?

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#### LloydGM

##### Silicon Dragon
Can anyone offer advice on how to calculate the amount of sugar (corn/dextrose, in my case) I'd need to add to each bottle when bottling partially-carbonated beer?

For example, with 6 gallons of ale sitting in a FermZilla, 15 PSI at 70F degrees at the end of fermentation. I can easily bottle with a counter pressure bottle filler, but I know that the beer currently has insufficient carbonation so that if I were to bottle it as-is, when a refrigerated bottle gets opened, it would be under-carbonated. I'm sure that if I could calculate the needed amount of sugar, I could ensure that each bottle would increase carbonation to the proper levels.

One thought I had was using the following steps, but maybe I'm over-thinking it or maybe I'm missing something?
1. Determine the CO2 volume in the FermZilla.
2. Determine the desired CO2 volume if it were fully-carbonated.
3. Subtract 1 from 2, giving the CO2 volume delta I'd need to attain with sugar.
4. Use a carbonation calculator to determine the amount of sugar needed to get that delta.

Also:
I'm using only bottles because I can't use a keezer/kegerator at this time.
I know I can increase PSI in the fermenter, and I may choose to do this later, though that gets uncomfortably close to the limit of a FermZilla's pressure rating.
I could also xfer the beer to a keg, force-carbonate it further, and then bottle it.
Yes, I know I could easily carbonate into corny kegs, and I might try this later, too, just for simplicity's sake.
My bottling technique pre-FermZilla was adding 5.8 - 6oz of dextrose into a bottling bucket, then bottling.

#### hotbeer

##### Opinionated Newb
HBT Supporter
Partially carbonated beer? You are just talking about the typical amount of carbonation at normal conditions that is in your beer as a result of fermentation aren't you? Or did you mess up and not put enough sugar or wort in a batch and it didn't carbonate to your expectation?

Just use any of the priming sugar calculators that have the type sugar you are using. Here is one....

They already take into account the dissolved CO2 from fermentation.

Though if you search for a beer priming sugar calculator for pressure fermented beer then you might find something better.

#### DBhomebrew

##### Supporting Member
HBT Supporter
Partially carbonated beer? You are just talking about the typical amount of carbonation at normal conditions that is in your beer as a result of fermentation aren't you? Or did you mess up and not put enough sugar or wort in a batch and it didn't carbonate to your expectation?

For example, with 6 gallons of ale sitting in a FermZilla, 15 PSI at 70F degrees at the end of fermentation.

#### hotbeer

##### Opinionated Newb
HBT Supporter
@DBhomebrew ... Some aspects of reading comprehension are tough when you have certain types of adult ADHD.

OP
OP

#### LloydGM

##### Silicon Dragon
Aye, by "partially carbonated", using the example above (my actual current batch I'm staring at), it's at 15 PSI in a FermZilla at 70F. If I pushed PSI to around 30, (32-ish, iirc) I'd get the right CO2 volume for 70F. The amount of CO2 in the FermZilla is only roughly half what I'd need if I were to bottle it as-is at 70F. This BYO page refers to it as "residual carbonation": Carbonation Priming Chart - Brew Your Own

I see 3 options:
1. Add dextrose to each bottle, then use counter pressure bottle filler to bottle. The extra sugar in each bottle would hit my target CO2 volume in a week or so.
2. Xfer the beer to a keg, ramp up PSI for a week, then bottle w/ CPBF. I've got 6gal, 5gal kegs, so 1gal would go into a 2nd keg, or I could go 3gal in each.
3. Push the PSI in the FermZilla, but I'm hesitant to do so since it gets awfully close to the pressure limit.

OP
OP

#### LloydGM

##### Silicon Dragon
@DBhomebrew ... Some aspects of reading comprehension are tough when you have certain types of adult ADHD.
ROFLMAO You pegged me squarely on da nosey! It makes me a great software engineer, but my wife hates it when I occupy the kitchen.

OP
OP

#### LloydGM

##### Silicon Dragon
Though if you search for a beer priming sugar calculator for pressure fermented beer then you might find something better.
I've tried but will try some more, thx!

#### hotbeer

##### Opinionated Newb
HBT Supporter
In my case it's just that I skim too fast through what a person writes and miss some of the dots between the beginning and end. Sometimes I jump the gun and miss the end entirely!

Also is seems a few of points related by others take longer to gel in my mind as to their relevance.

#### hotbeer

##### Opinionated Newb
HBT Supporter
I looked around quickly and there really isn't much that I found easily on bottling pressure fermented beer. Most everything is about everything before the bottling step.

I suppose if you don't have a pressure fermenter bottler, then thing to consider is maybe just releasing the pressure 12 hours or more prior to bottling and just using the amounts of priming sugar the other calculators give for beer at normal atmospheric pressure.

I didn't find anything that lets you easily guess what amount of sugar to use for something at more than 1 atmosphere.

OP
OP

#### LloydGM

##### Silicon Dragon
I suppose if you don't have a pressure fermenter bottler, then thing to consider is maybe just releasing the pressure 12 hours or more prior to bottling and just using the amounts of priming sugar the other calculators give for beer at normal atmospheric pressure.
Oh yeah, great minds do think alike! That's exactly what I did for my last 2 batches. It's because, no matter how much I search & read, I haven't found a good interim solution yet. Eventually, I'll have \$\$ to build my keezer, but I won't start buying parts until I'm 100% ready...I'm an perfectionist. And ADHD. And I'm already over-budget until at least Xmas. <cry>

I think I'll spend today experimenting with several ideas. When I'm done, maybe I'll be down to just 5gal in the FermZilla, then I could just xfer it to a keg, push the PSI to 30-ish, and bottle directly.

(I think I'm cursed, having gotten a great deal on a pack of reconditioned ball lock corny kegs, now I feel compelled to use them, lol.)

#### MikeCo

##### Supporting Member
HBT Supporter
I would think using a carbonation chart for temperature and pressure would give you the CO2 volume at 70F, and then you could add priming sugar to get the remaining desired CO2 volumes as you have suggested. The only parameter in the calculators to beware of is the beer temperature, which is used to calculate residual CO2. I think you'll want to assume no residual CO2 in the calculation, or the calculated sugar addition will be too high.

Probably the safest way is your suggestion of force carbonating in a keg and bottling from that.

#### Ricochet67

##### New Member
Hola mis Panas, una pregunta, me equivoqué y agregué muy poco azúcar de cebado para obtener 3.4 Volumen de Co2, en mi primer lote de cerveza Hefeweizen, ¿Se solucionará si lo dejo más tiempo en carbonatación, 3 o 4 semanas?

#### hotbeer

##### Opinionated Newb
HBT Supporter
Hola mis Panas, una pregunta, me equivoqué y agregué muy poco azúcar de cebado para obtener 3.4 Volumen de Co2, en mi primer lote de cerveza Hefeweizen, ¿Se solucionará si lo dejo más tiempo en carbonatación, 3 o 4 semanas?
The translation....... (at least google's version of the translation)

Hello my Panas, a question, I was wrong and I added very little priming sugar to obtain 3.4 Volume of Co2, in my first batch of Hefeweizen beer, will it be solved if I leave it longer in carbonation, 3 or 4 weeks?

Not quite certain what you are asking. Are you saying you planned for 3.4 vols and it's not achieved what you think is 3.4 vols of carbonation? If so, it's possible you might get more if you wait longer and properly calculated the amount of sugar. As well, that you evenly mixed the sugar into the beer if you used a priming pot to do it all at once. Or added the perfect and exact amount to each bottle.

If you are getting your beer really cold before opening and tasting it, then maybe the cold temperature is making them seem not so well carbonated. Let them warm up some. I tend to like beer best when it's temperature is about 50°F (10°C).

Oh just my 2¢... For a new question when you aren't the OP, you should start your own thread. Then conversations won't get confused. Though admittedly I'm guilty of the same thing more often than I'd like to be.

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#### Ricochet67

##### New Member
Hello Hotbeer, thanks for your advice, if I was planning to add 3.4 Vol CO2 yo my Hefeweizen beer according to the recipe, use the BrewersFriend calculator and Mix corn Sugar with my beer in priming pot, but I made a mistake in the required volume and wrote 2.4 Vol, being correct 3.4 Vol and adding less corn sugar, sorry for not using my own thread.

#### hotbeer

##### Opinionated Newb
HBT Supporter
2.4 vols is still enjoyable. I wouldn't worry about it. Just drink it when it's time and move on to your next batch.

If you also keg beer, then maybe dump it in a keg and carbonate it with CO2 to your desired level. But for bottled beer carbonating naturally, I'd just accept that it's not quite what you hoped for. It'll still be good. Especially after you have one or two!

#### Ricochet67

##### New Member
ok, Thank you Hotbeer

#### DuncB

##### Well-Known Member
Did we get any solution to this?
I have a Belgian golden strong lagering in a pressure fermenter at 1 celsius and 10 psi. So has CO2 vols of 2.6 I want to use my counter pressure bottle filler and add priming sugar and fresh yeast to get 4 vols of CO2 as per Duvel.
I can't seem to get the carbonation calculators to work this out.
Or is it a case of just working out the sugar required for the difference ie a target of 1.4 vols on top of say a theoretical 1 vol of prexisting carbonation?

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
HBT Supporter
Can anyone offer advice on how to calculate the amount of sugar (corn/dextrose, in my case) I'd need to add to each bottle when bottling partially-carbonated beer?

For example, with 6 gallons of ale sitting in a FermZilla, 15 PSI at 70F degrees at the end of fermentation. I can easily bottle with a counter pressure bottle filler, but I know that the beer currently has insufficient carbonation so that if I were to bottle it as-is, when a refrigerated bottle gets opened, it would be under-carbonated. I'm sure that if I could calculate the needed amount of sugar, I could ensure that each bottle would increase carbonation to the proper levels.

One thought I had was using the following steps, but maybe I'm over-thinking it or maybe I'm missing something?
1. Determine the CO2 volume in the FermZilla.
2. Determine the desired CO2 volume if it were fully-carbonated.
3. Subtract 1 from 2, giving the CO2 volume delta I'd need to attain with sugar.
4. Use a carbonation calculator to determine the amount of sugar needed to get that delta.

Also:
I'm using only bottles because I can't use a keezer/kegerator at this time.
I know I can increase PSI in the fermenter, and I may choose to do this later, though that gets uncomfortably close to the limit of a FermZilla's pressure rating.
I could also xfer the beer to a keg, force-carbonate it further, and then bottle it.
Yes, I know I could easily carbonate into corny kegs, and I might try this later, too, just for simplicity's sake.
My bottling technique pre-FermZilla was adding 5.8 - 6oz of dextrose into a bottling bucket, then bottling.
The calculation procedure you outline is correct. The key is determining the carbonation level of the beer before priming, so you can figure out how much sugar to add.

If you pressure ferment at a known pressure and temperature, there is a simple equation you can use to determine the starting volumes of carbonation:

V = (P+14.695)*(0.01821+0.090115*exp(-(T-32)/43.11))-0.003342​
Where P is the gauge pressure and T is temperature in °F​
I whipped up a quick spreadsheet to do the calculations, and attached it below.

Brew on

#### Attachments

• Priming Calculator for Pressure Fermented Beer.zip
14.9 KB · Views: 0
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OP

#### LloydGM

##### Silicon Dragon
After action report:
I tried several things with varying degrees of success and found it was easiest and less messy (as in beer volcanoes) to simply depressurize the FermZilla, rack to a bucket, add dextrose, and bottle. Old school, but clean and super easy.

One might ask, "why use a pressure fermenter then?" and that's a great question. Well, it ferments much faster (e.g. a vanilla stout fully fermented in 3 days) there have been no off-flavors, so it's a win-win. I don't even see losing that natural CO2 as a loss since I get it back for near-free with the dextrose. Next up is a lager at room temp, oh yeah! (It'll be nice not having to wait for it to freeze outside just so my garage gets cold enough. Plus, it's a real drag hauling a fermenter down all the stairs into the garage.)

I'm still anxious to gain all advantages of pressure fermentation when I'm able to chill it properly.

Everyone, thanks for the help. I really appreciate everyone's ideas and advice. (PS that spreadsheet was a nifty idea, but I think I'll convert it as I'm a software engineer and, of course, have to code everything, lol.)

#### DuncB

##### Well-Known Member
@doug293cz
Thank you for the spread sheet, I've tried it with my data mentioned in post 17
" I have a Belgian golden strong lagering in a pressure fermenter at 1 celsius and 10 psi. So has CO2 vols of 2.6 I want to use my counter pressure bottle filler and add priming sugar and fresh yeast to get 4 vols of CO2 as per Duvel."

The spreadsheet works out the correct pressure certainly within my margin of error as I can't guarantee the exact pressure. But the sugar addition doesn't seem right as it's a negative figure. I've attached my inputs as it suggests I need less sugar to get 4 vols even though it's only at 2.6 vols!!

EDIT Now realised that I didn't press enter after filling that field with the number 4 and it has calculated the figure of 4.25 oz of priming sugar.

Just checking what do I do to get the figure for using dry dextrose? do i just put Dextrose in the field?

Brilliant work

Edit again Found a drop down option, you make it too easy!

Last edited:

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
HBT Supporter
@doug293cz
Thank you for the spread sheet, I've tried it with my data mentioned in post 17
" I have a Belgian golden strong lagering in a pressure fermenter at 1 celsius and 10 psi. So has CO2 vols of 2.6 I want to use my counter pressure bottle filler and add priming sugar and fresh yeast to get 4 vols of CO2 as per Duvel."

The spreadsheet works out the correct pressure certainly within my margin of error as I can't guarantee the exact pressure. But the sugar addition doesn't seem right as it's a negative figure. I've attached my inputs as it suggests I need less sugar to get 4 vols even though it's only at 2.6 vols!!

EDIT Now realised that I didn't press enter after filling that field with the number 4 and it has calculated the figure of 4.25 oz of priming sugar.

Just checking what do I do to get the figure for using dry dextrose? do i just put Dextrose in the field?

Brilliant work

Edit again Found a drop down option, you make it too easy!

View attachment 785804
Here's what I get with your inputs:

Did you accidentally modify one of the formula cells? Could you zip up your version of the sheet, and send it to me by PM?

Brew on

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
HBT Supporter
Just checking what do I do to get the figure for using dry dextrose? do i just put Dextrose in the field?
Do you really have anhydrous dextrose? That stuff is very hydrophilic, and tends to clump up, which is why most of what is available is dextrose mono-hydrate (e.g. corn sugar.)

Brew on

#### DuncB

##### Well-Known Member
Here's what I get with your inputs:

View attachment 785845

Did you accidentally modify one of the formula cells? Could you zip up your version of the sheet, and send it to me by PM?

Brew on
@doug293cz
I found out that I hadn't pressed enter after putting the data into the field, my screen grab shows the desired carbonation with a green box around it. I thought it was going to adjust the outputs on the fly forgetting it was a spreadsheet.
When I pressed enter it came out exactly as your calculation. Probably not made clear by me in my edit.
I have corn sugar I was confusing it with corn syrup which I have but don't use or need to use. I'd been told elsewhere by @VikeMan that the anhydrous form is very hydrophillic and not really available so I will just be using the dextrose mono-hydrate for priming.

I'll let you know how it goes with the carbonation outcome in about a month. Great tool and I've saved it for future use.

#### doug293cz

##### BIABer, Beer Math Nerd, ePanel Designer, Pilot
Staff member
Mod
HBT Supporter
@doug293cz
I found out that I hadn't pressed enter after putting the data into the field, my screen grab shows the desired carbonation with a green box around it. I thought it was going to adjust the outputs on the fly forgetting it was a spreadsheet.
When I pressed enter it came out exactly as your calculation. Probably not made clear by me in my edit.
I have corn sugar I was confusing it with corn syrup which I have but don't use or need to use. I'd been told elsewhere by @VikeMan that the anhydrous form is very hydrophillic and not really available so I will just be using the dextrose mono-hydrate for priming.

I'll let you know how it goes with the carbonation outcome in about a month. Great tool and I've saved it for future use.

Brew on

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