Priming calculators wrong?

[mrchicken]

Ok I have been racking my brain and asking a bunch of questions on my poor carbing issues.

Been using the northern brewer priming calculator.

Today I bottled my ale kit that came with my fermentor. It had 5 oz of corn sugar for priming. When I checked it against the norther brewer priming calculator it said use 4.04 oz corn sugar. A significant difference !

Then I looked up the brewers friend priming calculator and it suggests using .5oz more than the Northern Brewers calculator for the exact same beer specs.

Has anybody else had a problem with undercarbed beer using the NB priming calculator?

 

[Yooper]

Ok I have been racking my brain and asking a bunch of questions on my poor carbing issues.

Been using the northern brewer priming calculator.

Today I bottled my ale kit that came with my fermentor. It had 5 oz of corn sugar for priming. When I checked it against the norther brewer priming calculator it said use 4.04 oz corn sugar. A significant difference !

Then I looked up the brewers friend priming calculator and it suggests using .5oz more than the Northern Brewers calculator for the exact same beer specs.

Has anybody else had a problem with undercarbed beer using the NB priming calculator?

Yes. Priming calculators take the temperature and desired carbonation volume and guestimate the likely volume of c02 in the finished beer. So, with those variables, you could end up with bottle bombs or undercarbed beer at times.

Generally, using 4-5 ounces of corn sugar per 5 gallons of finished beer will give you an acceptable carbonation level, like that of commercial bottled beers.

 

[ncbrewer]

Has anybody else had a problem with undercarbed beer using the NB priming calculator?

I've noticed that the NB calculator shows a little less sugar required. I use a formula that comes in between the two you looked up, targeting 2.6 volumes for most beers. It seems about right. I do make an estimate of how much beer I will actually rack to the bottling bucket, rather than use the amount in the fermenter.

I think it's a good idea to use some sort of calculator that takes temperature into account if you vary the temperature from batch to batch. If it's warmer, it should have less CO2 dissolved - I think that should be accounted for.

 

[beermanpete]

I have been using the Brewer's Friend calulator and tend to get lower carbonation than I expect/want as well.

 

[TomVA]

I have found the same sort od discrepancies among priming sugar calculators:

https://www.homebrewtalk.com/showthread.php?t=619337

TomVA

 

[flars]

The best carbonation calculator to use is the one you use consistently. The same calculator, along with good notes in your brew log, will give you the best results.

 

[IndyBlueprints]

This may be simplistic, but for 20+ years, for a 5 gallon batch I added 3/4 to 7/8 cup of corn sugar before bottling. Then let them bottle condition at room temp for 2-3 weeks. Pretty much worked every time.

 

[kh54s10]

I use Northern Brewer's calculator and find that it does a pretty good job. I have had 2 gushers, both were big, dark beers and I had selected lower carbonation levels for those so there was something else going on. I think that most kits include the 5 ounce packs. Usually that would not be too much, but also not truly to carbonation levels for a given style. I guess it is just easier to measure one amount and include it in all kits rather than different amounts for different kits.

As noted the fermentation temperature the beer reached during fermentation will have an effect on the amount of co2 in the beer before adding the priming sugar, so the amount for different beers will be different.

 

[Silver_Is_Money]

This may be simplistic, but for 20+ years, for a 5 gallon batch I added 3/4 to 7/8 cup of corn sugar before bottling. Then let them bottle condition at room temp for 2-3 weeks. Pretty much worked every time.

I also used the 3/4 level cups of corn sugar for nominal 5 gallon batches method for many years (based upon the classical old school guidance to do just this), until I eventually discovered that it was giving me (give or take, based upon my fermentation temperature) about a whopping 2.85 volumes of CO2, whereas a much lower 2.5 volumes is more the US norm for commercial brews packaged in bottles.

If keeping it just this simple is the goal however, then 2/3 level cups of corn sugar is more in line with the goal, as it will generally achieve about 2.6 volumes of CO2. Still a tad on the high side perhaps, but not close to as overly high as 2.85.

And lastly, 1/2 level cup of good old granulated white table sugar for a 5 gallon batch will roughly hit the lower but totally acceptable UK bottle carbonation standard of ~2.3 volumes of CO2. Years ago it was considered taboo to use granulated table sugar to bottle carbonate based upon the fear of its imparting an off flavor 'twang', but at this low level of usage the fear was totally unfounded.

I've personally pretty much settled upon using 110 to 112 grams of granulated white table sugar for a nominal 5 gallon (53 to 54 x 12 Oz. bottles) yield, as I prefer weight measurement over volume measurement.

FWIW: My 1/2 cup measure delivers on average 102 grams of granulated white table sugar when filled and leveled off.

 

[C-Rider]

I've used BeerSmith for years and only had one under carbed bier.

 

[Silver_Is_Money]

I use my own spreadsheets for computing nigh on everything that is brewing related now, and mine computes that 2/3 cup of corn sugar should yield approximately the following (with rounding) for a 5 gallon yielding batch:

1) 55 degrees max temp reached during ferment and rest and bottling: 2.8 volumes CO2
2) 60 degrees max temp reached during ferment and rest and bottling: 2.7 volumes CO2
3) 65 degrees max temp reached during ferment and rest and bottling: 2.6 volumes CO2
4) 75 degrees max temp reached during ferment and rest and bottling: 2.5 volumes CO2
5) 85 degrees max temp reached during ferment and rest and bottling: 2.4 volumes CO2

Only for the case of 55 degrees or below should there be any nominal reason to be concerned. The solution for 55 degrees or below is to drop down to 1/2 cup (which drops you to a rounded 2.4 volumes for specifically the case of 55 degrees).

Warning/Disclaimer: I may have programmed it incorrectly. And even if programmed correctly, I have no idea with regard to the accuracy of the formulas. Use at your own discretion. No guarantees or waranties expresssed or implied. YMMV

 

[PADave]

Ok I have been racking my brain and asking a bunch of questions on my poor carbing issues.

Been using the northern brewer priming calculator.

Today I bottled my ale kit that came with my fermentor. It had 5 oz of corn sugar for priming. When I checked it against the norther brewer priming calculator it said use 4.04 oz corn sugar. A significant difference !

Then I looked up the brewers friend priming calculator and it suggests using .5oz more than the Northern Brewers calculator for the exact same beer specs.

Has anybody else had a problem with undercarbed beer using the NB priming calculator?

Every kit gets a 5 oz pack. That's just the size it comes in. I've settled on using 4 oz for just about all my brews. Using a scale and weighing is going to be more accurate than a measuring cup.

 

[mrchicken]

Probably a dumb question but....
How does the max temp during fermentation affect CO2 in solution after primary? I would think that an unpressurized fermentor would loose CO2 as time passes and the beer temp at BOTTLING would be far more accurate a measure of how much CO2 remains in the beer. Especially if the beer was left in primary for a week or more after fermentation is done.... ???

 

[Yooper]

Probably a dumb question but....
How does the max temp during fermentation affect CO2 in solution after primary? I would think that an unpressurized fermentor would loose CO2 as time passes and the beer temp at BOTTLING would be far more accurate a measure of how much CO2 remains in the beer. Especially if the beer was left in primary for a week or more after fermentation is done.... ???

Colder temperatures "hold" c02 in solution more than warmer temperatures that is, more c02 exits out the airlock at warmer temperatures.

It doesn't matter in the case you mention, and using the temperature at bottling may well be fine. But say you ferment a lager at 55 degrees, then do a diacetyl rest at 65 degrees, then lager the beer at 34 degrees for 8 weeks.

You would use the temperature of 65 degrees, since once the c02 is released after fermentation ends, no new c02 is created to go back into solution.

 

[TomVA]

CO2 is dissolved in the wort, and the amount dissolved depends on the temperature. Once active (CO2 producing) fermentation is done, if the wort is warmed some CO2 will be released and less will be in solution, thus requiring more priming sugar. If the wort is then cooled, more CO2 will not go back into solution since there is no more CO2, so the amount of CO2 in solution at the time of bottling is dictated by the highest temperature the wort reached after active fermentation has finished.

TomVA

 

[Silver_Is_Money]

See this link:

https://www.homebrewtalk.com/showthread.php?t=618996

At 50 degrees F. "max temp experienced pre-capping" your beer retains (holds on to) roughly 1.2 volumes of CO2.
At 85 degrees F. "max temp experienced pre-capping" your beer retains (holds on to) roughly 0.7 volumes of CO2.

Therefore you are not (via bottle priming) carbonating flat beer, but rather you are additionally carbonating already somewhat carbonated beer. And the degree (quantity) of "somewhat carbonated" already inherently present within your beer before the cap goes on the bottle is temperature related....

 

[Yooper]

See this link:

https://www.homebrewtalk.com/showthread.php?t=618996

At 50 degrees F. 'max experienced' pre-bottle carbonation beer retains (holds on to) ~1.2 volumes of CO2.
At 85 degrees F 'max experienced' pre-bottle carbonation beer retains (holds on to) ~0.7 volumes of CO2.

And that is one of the reasons I hate those priming calculators!

First, let's use my example above at of a lager. If you use 65 degrees, the highest temperature post-fermentation, the Tasty Brew calculator says to use 4.0 ounces of priming sugar. It auto defaulted to 2.4 volumes by "style".

For 34 degrees, the priming calculator shows 2.0 ounces of corn sugar. In other words, half as much.

The other part of it is that the "recommended" c02 volumes are wonky. Most people who buy commercial beer are accustomed to a bottled beer carbonated to 2.4-2.5 volumes. When you click on ordinary bitter, the co2 volume recommended is .75 volumes- in other words totally flat. That may be true of real cask ale, but most people who are going to the trouble of bottling their beer don't want it flat. Anyway, the recommended amount of priming sugar in that case is -2.3 ounces. That's right- negative 2.3 ounces.

For a weizenbock, the recommended c02 volume is 4.74 volumes- which would be gushers at best, bottle bombs at worst.

That's why I use .75 ounce- 1 ounce of priming sugar per finished gallon of beer in my own bottling. I might go with .75 ounce for a lower carbonation level, and 1 ounce for a more carbonated beer, but over all they are pretty much what you'd expect from a bottled beer's carbonation level. Often, I just go with 4.5 ounces of corn sugar per 5 gallon batch and call it good.

It works well, never had a bottle bomb or a gusher or undercarbed beer in 12 years. I don't bottle often these days, but I still go with the same technique.

 

[Silver_Is_Money]

Often, I just go with 4.5 ounces of corn sugar per 5 gallon batch and call it good.

It works well, never had a bottle bomb or a gusher or undercarbed beer in 12 years. I don't bottle often these days, but I still go with the same technique.

How well does this compare with settling upon 2/3 level cup of volume measured corn sugar into 5 gallons for most bottle priming?

 

[Silver_Is_Money]

From a pressure perspective, a capped bottle of "2.85 Volumes CO2" beer sitting in a closet at 85 degrees F. is generating 50 PSI of pressure (for said conditions). Glass beer bottles (new ones, not used, aged, and thereby potentially weakened) begin to let go and fail at about 60 PSI. That's way too close for comfort for me. No desire to ever experience bottle bombs here. The old standby advice to add 3/4 cup of corn sugar to a 5 gallon batch is like playing with fire.

I've heard that PET plastic bottles don't let go until somewhere between 80 and 120 PSI. Take this for only the hearsay value it contains,

 

[Yooper]

How well does this compare with settling upon 2/3 level cup of volume measured corn sugar into 5 gallons for most bottle priming?

I have no idea. Some sugar is finely granulated, some isn't, and I've never measured it that way. I think the only "right" way to do it would be by weight.

 

[Silver_Is_Money]

I agree that volume measurement has inherent and potentially serious flaws.

Per the Northern Brewer calculator, 2/3 cup of corn sugar nominally weighs about 4.66 ounces.

 

[Silver_Is_Money]

One of the biggest potential mistakes people can make is in confusing volume ounces with weight ounces, or visa-versa.

 

[mrchicken]

You guys are awesome! I am learning a ton !

 

[ncbrewer]

You guys are awesome! I am learning a ton !

If you're brewing 50 years from now, you'll still be learning. That's one of the things I love about brewing.

 

[Silver_Is_Money]

Probably a dumb question but....
How does the max temp during fermentation affect CO2 in solution after primary? I would think that an unpressurized fermentor would loose CO2 as time passes and the beer temp at BOTTLING would be far more accurate a measure of how much CO2 remains in the beer. Especially if the beer was left in primary for a week or more after fermentation is done.... ???

If you wait long enough post fermentation you will eventually not see any more bubbles coming through your airlock (which is one of the primary means by which you determine fermentation completion), but the beer in the fermenter is still at this juncture theoretically as fully saturated with "volumes" of CO2 as it can be based upon its past/present temperature history.

That said, there is still some serious ambiguity (in my mind at least) in such an ideal case as for the above. For example: If the maximum temperature point is reached at 65% of the way through fermentation, at this juncture the vessels ability to hold CO2 volumes must be at its very lowest. But what if post this juncture things cool down a bit, if for no other reason than because on the fermentation down-side the diminishing yeast activity is not emitting as much internal heat energy, and since the saturation level "potential" of the beer increases as its temperature decreases, the volumes of CO2 present in the beer for this example will not reflect that of the highest temperature reached, because active fermentation is still going on for yet another 35% of ABV generation to final completion (yeast exhaustion or starvation culminating in hibernation). Therefore, I theorize (surmise/propose) a modification in that one should only consider the maximum temperature history of the beer somewhere post its most active period of (aggressive) fermentation (and perhaps better, as late in the game as 90% of the way to fermentation completion), and use this temperature as your priming calculators max temperature history input value. Comments on this modification proposal are welcome.

 

[Silver_Is_Money]

A meter designed to detect and read out in units of dissolved CO2 (akin to existing dissolved oxygen meters) would be a handy item to use just before adding priming sugar.

 

[Silver_Is_Money]

Are some the various priming calculators wrong because they compute differing amounts of sugar to be added? You have to first know where you are at in order to plan and then execute moves to take you where you subsequently want to be. But here is a situation wherein no one actually knows specifically where their beer is at with regard to its quantitative dissolved CO2 content immediately before they toss in the priming sugar, so no one can truly know where it will actually end up. The primary reason why the various priming calculators differ as to how much sugar you need to add is because they are making somewhat different educated guesses as to where the beer is initially at before the addition of sugar with respect to its quantity of already present dissolved CO2. Not some, but rather all of the various priming calculators are wrong because they are all reduced to guessing. I believe this is the best answer I can offer to the OP's question.

As an aside: For all-grain brewers trying to best determine how to hit a mash pH of precisely 5.4, the above also applies with respect to the mash pH software calculators.

 

[Silver_Is_Money]

The problem goes deeper yet than for my above post. No two documented root data sources can seem to agree upon exactly how much CO2 there will actually be discovered to be left dissolved in beer post its fermentation, even if all of the requisite historical/quantitative factors for the beer are precisely known, as well as for the science of how many volumes of CO2 a given quantity of added sugar will contribute being rock solid. Various root level data charts and/or math model formulas display or compute varying answers for the initial dissolved CO2 volumes for every temperature that one cares to look at. So even if you think you know all of the pertinent factors that should permit you to pin down (define) your precise starting point, you still don't know your precise starting point, because the experts themselves can't unify upon what the actual volumes of dissolved CO2 starting point should be for any given temperature. This introduces problem #2 for the calculators. They have not all grasped hold of the same root source (baseline) information upon which to build their models. Their output is a consequence of their source data as much as it is a consequence of your input data (I.E., max temp and volumes desired), and grasping for the "correct" root source data is almost akin to grasping for straws.

So in the end you can pretend that this is complicated science beyond your wildest imagination (such as it is), and pick the priming sugar program of your choosing by magical whim, or more importantly because it looks nice, or because it is the easiest one to operate, or because all of the other people you know (who are clearly just as misguided as you are in all of this) have settled upon a favorite which they "know" to be correct, wherein you might be conceived to be highly unpopular (or crazy) if you choose some other program, etc..., or finally (unless you are bottling cold lagers that have never been heated up at any juncture) you can just as easily add 2/3 level cups of corn sugar for a 5 gallon batch (or a weight equivalent to this for even greater precision and repeatability) and move on. If for multiple decades the standard and virtually unchallenged advice was to add 3/4 cups of corn sugar, and for decades people happily made bottled beers that did not directly explode as a consequence of this, then the likelihood of explosions from adding 2/3 cup must be somewhat less.

 

[TomVA]

Or just calculate the priming sugar on three different calculators and average the results! Can't be too far off that way.

TomVA

 

[ncbrewer]

Therefore, I theorize (surmise/propose) a modification in that one should only consider the maximum temperature history of the beer somewhere post its most active period of (aggressive) fermentation (and perhaps better, as late in the game as 90% of the way to fermentation completion), and use this temperature as your priming calculators max temperature history input value. Comments on this modification proposal are welcome.

For what it's worth, I agree. Don't remember where, but I've read at least one article that instructs using the highest temperature post fermentation.