Hey Martin! A question about bicarbonate

[ajdelange]

Sorry for steering this discussion a bit off course but I have a question regarding bicarbonate. Are there any advantages, taste-wise, to having bicarbonate in your brewing water?

No. Taste some baking soda dissolved in water and see if you think that's a pleasant taste.

I know that if I choose a particular style in the Bru'n Water spreadsheet, it will give a "desired" bicarbonate level. I brew exclusively with RO water which I have a water report for (with typical CaCl2, CaSO4 and acidulated malt additions) using BIAB and make a lot of milds and ESBs. If bicarbonate adds nothing to the taste profile of the beer, then it seems silly for me to be adding NaHCO3 to hit the desired level just so I can neutralize it with an extra ounce or two of acidulated malt.

That would indeed be silly because 'neutralization' here doesn't mean what you may remember from your high school chemistry where it means bringing the pH to 7 (neutral) but rather bringing the pH to around 5.3 where 91 mg of each 100 mg of bicarbonate added will be converted to CO2 gas. If the 'desired' level of bicarbonate requires you to add acid to get proper mash pH then it is not actually desired at all.

The 'desired' level idea is relict from the days when we thought that to have a good Munich style beer we needed to have water like that in the Isar. That's not really so. To have a good Munich style beer the stylistic ions (chloride and sulfate) and total minerals should be in concentrations similar to those in the liquor used by the breweries which may have small resemblance to the source water though in many cases it will (Pilsen water). The Isar contains quite a bit of bicarbonate but the first thing a Munich brewer does is get rid of it. The desired level for bicarbonate is generally 0. There will be cases where the proportion of high kilned malt used in a brew will pull the pH too low if there is no offsetting alkalinity and in those cases some is needed. One could, I suppose, merge that into a 'desired' profile but if that is done it apparently leads to the kind of confusion you are experiencing which, if I understand it, is that you selected a profile, merged it with a grain bill, got a high pH and added acid to correct the high pH. Better, IMO, to determine typical sulfate and chloride levels for the beer you want to brew, set those with salts, see what the pH estimate is and add one or the other (but not both) of bicarbonate or acid to correct.

But if bicarbonate does, at low levels, add something positive to the beer, then I'd guess I'd add it.

If you brew a beer with no bicarbonate at all surviving and carbonate it to 2 volumes assuming its pH to be 4.3 it will contain 50 mg/L bicarbonate from the added gas. If you started with water with alkalinity 100 when you made this beer only about 1.3 mg/L bicarbonate from that source would be left in the finished beer so yes, finished beer does contain bicarbonate but it comes from carbonation, not bicarbonate in the water (or the vast preponderance of it does).

I haven't worried about it and just went with the very low level of bicarbonate that is in my RO water even if it's far below the "desired" level for a style/color of beer. Everything seems ok to me but I'd change protocols if I heard different from the water experts here. Thanks!

It's very astute of you to have picked up on this. It isn't really something that should keep you awake at night, though. If you add some bicarbonate and then some phosphoric acid to 'neutralize' it then you have effectively added some sodium phosphate to your beer. No need to do that but a little won't hurt.

 

[Yooper]

Sorry for steering this discussion a bit off course but I have a question regarding bicarbonate. Are there any advantages, taste-wise, to having bicarbonate in your brewing water? I know that if I choose a particular style in the Bru'n Water spreadsheet, it will give a "desired" bicarbonate level. I brew exclusively with RO water which I have a water report for (with typical CaCl2, CaSO4 and acidulated malt additions) using BIAB and make a lot of milds and ESBs. If bicarbonate adds nothing to the taste profile of the beer, then it seems silly for me to be adding NaHCO3 to hit the desired level just so I can neutralize it with an extra ounce or two of acidulated malt. But if bicarbonate does, at low levels, add something positive to the beer, then I'd guess I'd add it. I haven't worried about it and just went with the very low level of bicarbonate that is in my RO water even if it's far below the "desired" level for a style/color of beer. Everything seems ok to me but I'd change protocols if I heard different from the water experts here. Thanks!

Bicarbonate is only desirable in the amount needed to get the proper mash pH, say with a stout or some style with a lot of dark roasted grains that can drive the mash pH too low. That isn't all that common- most people suffer from a too-high mash pH, and rarely from too low, but it is possible in recipes with a heavy amount of roasted grains.

I believe Martin (mabrungard) said that the reason that the profiles have a bicarbonate level listed is just because the waters in that profile happened to have that much bicarbonate. It doesn't mean that it is a 'desirable' amount at all. You only want the alkalinity in the amount needed to ensure a proper pH. In this case 'less is more' does apply, as generally you want low alkalinity in your brewing water.

 

[dilluh]

No. Taste some baking soda dissolved in water and see if you think that's a pleasant taste.

That would indeed be silly because 'neutralization' here doesn't mean what you may remember from your high school chemistry where it means bringing the pH to 7 (neutral) but rather bringing the pH to around 5.3 where 91 mg of each 100 mg of bicarbonate added will be converted to CO2 gas. If the 'desired' level of bicarbonate requires you to add acid to get proper mash pH then it is not actually desired at all.

It's very astute of you to have picked up on this. It isn't really something that should keep you awake at night, though. If you add some bicarbonate and then some phosphoric acid to 'neutralize' it then you have effectively added some sodium phosphate to your beer. No need to do that but a little won't hurt.

Sorry for the fast and loose use of "neutralization" here - I know what you're getting at. I'm a chemist by trade though an inorganic synthesis one so it's been a long time since my days as a teaching assistant where I worked with acid/base equilibria regularly.

I guess at the end of the day I'd rather not have the extra Na from NaHCO3 just for the sake of it. I'll continue on as I've been doing with Ca, Cl and SO4 levels to my liking using gypsum and CaCl2 with acid malt to get me where I need to be pH-wise. I've thought to add MgSO4, but my fermentations appear to be plenty healthy so the wort must be getting enough Mg from the grains.

Thanks so much to Yooper and AJ for the quick replies! I've learned a lot by lurking/reading here (the water primer sticky was especially eye opening) and this was my first post. As a side note, the water primer thread made me wonder how many coffee/espresso shops pay much attention to their water chemistry.

 

[mabrungard]

As Lorena mentions, there is no target bicarbonate level in water, excepting that needed to produce an acceptable or desirable pH. Add bicarbonate or hydroxyl ion to the mashing water to meet that pH criteria.

On that side note, there happen to be a lot of studies by the coffee industry on desirable water ionic content. But I don't see any coffee shops adjusting their water quality other than many shops using RO to primarily reduce the hardness so that their machines don't accumulate scale.

 

[dilluh]

This is pretty shocking (coffee water) to me considering how fanatic/obsessive many people are about their coffee preparation and how much they're willing to pay for a mediocre cup. I wonder if a shop could leverage this, advertise that they customize their water for particular brews, end up with better coffee and thus can charge more.

 

[Lukes1040]

I know this thread is old, but I have been searching for days to try to find a good answer as to why bicarbonate is specified in certain styles in water calculators if it is essentially an unwanted item in the brew. I have been using bru'n water lately and I do like the system (thanks Martin!), but I had yet to find an answer until now, buried deep in pages of the forum. Aj explained it very well and I just wanted to thank him for that post. It may as well be explained in the bru'n water pages, but I would suggest Martin make a disclaimer on the mash water page that draws Brewers attention to this fact. Just my opinion, but it may help further confusion to Brewers. Thanks again!

 

[ajdelange]

At the risk of repeating myself the art of predicting mash pH depends on keeping track of proton deficits (the number of protons it takes to move mash pH components from whatever pH they come to you at to the desired mash pH). Alkalinity is the proton deficit from water source pH to pH 4.5 (or thereabouts depending on the definition used). It's fairly simple to calculate proton deficit to a mash pH from the alkalinity. It is equally simple to get the proton deficit for a malt if someone has taken the appropriate measurements for you. In any case the question is as to how to express proton deficit. The obvious and standard unit is mEq/L. In north America the equivalent weight of calcium carbonate (50 mg/L) is used and alkalinity in those units, 'ppm as CaCO3', is 50*mEq/L. Martin has chosen to use his own units 'as bicarbonate' in which proton deficits are 61*mEq/L and compound the error by leaving out the 'as' and just calling it 'bicarbonate'. Setting aside the fact that the equivalent weight of bicarbonate depends on pH (it takes 61 mg bicarbonate to absorb 1 mEq of protons to pH 4 and below but it takes 1.25*61 mg to absorb 1 mEq to pH 5.6) the worst aspect of this is that when people see 'bicarbonate' as the field label they think it means bicarbonate. This causes lots of confusion, of course, to the wiser but those whose understanding is more limited readily accept that the distilled water to which they have added some lime is now supposed to contain bicarbonate and worry that it isn't exactly the amount of bicarbonate 'required' by the profile they are trying to match.

 

[rhys333]

Quick question about Bru'n Water and bicarbonate...

I'm brewing a porter with the following grist and it recommends adding a relatively high amount of baking soda. It has me second guessing myself and appreciate advice from the pros.

PORTER GRIST FOR 23L (6 US gal) BATCH:
2.8 kg 2 Row 1.75L (56%)
1 kg Wheat malt 2L (20%)
0.5 kg C60/40 blend (10%)
0.45 kg Brown malt 60L (9%) - I assigned as base malt in v1.18 B.W.
0.25 kg UK Chocolate 425L (5%)

It recommends dosing my 12.9L (3.4 gal) RO mash water with 0.8g gypsum, 1.3g CaCl2, 0.6g epsom, and the kicker... 3.0g baking soda. Relative amounts also added to my 15.1L (4 gal) sparge, excluding baking soda. Without acid, estimated mash pH = 5.39 in B.W.

Final estimated mineral concentrations: Ca: 50 / Mg: 5 / Na: 63 / SO4: 53 / Cl: 64 / Bicarb: 167.

Do I have this right? 3g baking soda and 167 ppm seems awefully high, and I'm concerned about sending the pH through the roof. Sodium is also getting up there. Thanks in advance!

 

[mabrungard]

Are you using the free version of Bru'n Water? If so, that 60+ppm sodium content is only present in the mash. When you add the sodium-free sparging water, that sodium content will be diluted. You have to perform that dilution calculation manually if you have the free version, but it's automatic in the supporter's version.

So the actual sodium content is in the 30 ppm range and that is entirely acceptable in a stout, as is 60 ppm.

Boosting the mashing pH in most stouts and porters is helpful to flavor.

 

[rhys333]

Are you using the free version of Bru'n Water? If so, that 60+ppm sodium content is only present in the mash. When you add the sodium-free sparging water, that sodium content will be diluted. You have to perform that dilution calculation manually if you have the free version, but it's automatic in the supporter's version.

So the actual sodium content is in the 30 ppm range and that is entirely acceptable in a stout, as is 60 ppm.

Boosting the mashing pH in most stouts and porters is helpful to flavor.

Thanks Martin. I am using the free version of Bru'n for the time being. Had success with pale beers, and dabbling again with darker brews that I've shied away from due to astringency issues in the past using other methods.

According to the spreadsheet my mash water has 71 ppm sodium, and finished water has 60 ppm. Also bicarb: 183 mash, 167 finished. If I need to do additional calculations to see actuals, are the differences I see due to something else, perhaps absorption?

 

[jhanlon]

Hi all,

I'm looking for help in attaining a target mash pH of 5.5 for a dark beer using Bru'N Watet (first time) while keeping bicarbonate levels under control. I've searched and searched but cannot figure this out.

I'm making an Oatmeal Stout (similar to Shakespeare featured on Can You Brew It) using 100% RO water, and after entering the grain bill and choosing 100% RO dilution, have an estimated mash pH of 4.64. To get up to an estimated pH of 5.5 (using picking lime), I have to drive the bicarbonate level up around 400. The only way I know to bring to bring that level down is to use an acid, which drops my pH. It's just a circle. Anyone know what I should do here?

Thanks,
Jason

 

[rhys333]

What's your grain bill?

 

[jhanlon]

Here it is.

 

[jhanlon]

This is about the best balancing act I can do to keep the estimate at 5.5, and have all other levels within an acceptable range (except bicarbonate, of course).

 

[mabrungard]

You don't need to bring the bicarbonate content down. It is only an indicator and not a target. The target is pH. If the estimated pH is where you want it, then the bicarbonate content is correct. The acids in the wort will neutralize the excess bicarbonate.

 

[jhanlon]

Martin, thank you for the reply. I did see the note in the spreadsheet stating that it is only in indicator, but the beginning of this thread (4 years ago!) discusses addressing excess bicarbonate.

"It is a balancing act. As AJ said, you have to attend to excessive bicarbonate in brewing water.

Bicarbonate is what I feel is the number one problem for most brewers. Tailoring that level to match the grist and reducing it to low level in sparging water makes all the difference in brewing."

Is reducing excess bicarbonate only necessary when you are out of proper acidification range (higher than ~5.8)?

 

[ajdelange]

If pH is too high it is because of a proton deficit that has not been neutralized by added acid, high kilned malts or protons released by the reaction of calcium with base malt. There are three sources of proton deficit:
1) Bases added to the mash or mash water by the brewer such as lime or sodium bicarbonate
2) Base and other light colored malts
3) Bases already in the water which usually are mostly bicarbonate but which, in high pH source waters, may include some carbonate and hydroxyl ions

If mash pH is high excess bicarbonate (either already in the water or added by the brewer) is a good thing to look for. But you should also check that you have the dark malt component(s) that is needed for your recipe as that cancels some proton deficit too.

Note that a peculiarity of Brun water is that it reports water's proton deficit as bicarbonate whether is is due to bicarbonate or something else. Most of the time bicarbonate in the water is responsible for its proton deficit so you will usually be OK with this but be careful in how you interpret the 'bicarbonate' field if you have used lime or the pH of the source water is high.

 

[xpops]

Since this thread is still going....

if i'm brewing a lager...starting with RO so very low alkalinity to begin with but require acid to hit a pH of 5.3, but that puts my bicarbonate (in brun'water) at -132...

i shouldnt be concerned with such a high negative number, providing my pH target is where i want it....correct??

NOTE* my calcium is only at 22....i could add CaCO3 to both increase Calcium and bicarbonate to get closer to zero, but it seems redundant to add alkalinity AND acid to same mash??

thanks for the clarification!

 

[ajdelange]

As I noted in #57 it is a peculiarity of Brun water that it represents acidity and alkalinity as bicarbonate which, while it is technically doable, confuses 99.99% of users as 99.999% of brewers and scientists do not use this representation. The other 0.001% know enough chemistry to figure out what he is doing. Most of the world uses mEq/L (a measure of the actual proton emission or absorption) and those who don't use a wide array of measures such as dH (German degrees), °F (French degrees) or, in the US, ppm as CaCO3. Bru'n water's representation is mEq/L expressed 'as bicarbonate'. To add to the confusion the 'as' is omitted which causes many to think that the number reported in the bicarbonate field actually represents the amount of bicarbonate ion in the water (which it does in many cases i.e. where the water is of pH < 8 and no acids or bases have been added to it - you got a negative bicarbonate indication because you added acid). Thus, if that field shows 30.5 the user is likely to conclude that there is 30.5 mg/L bicarbonate ion in the water even though there is, in fact, none (as if, for example, one added lime to distilled water). The number is, in fact, the alkalinity in mEq/L multiplied by 61, the equivalent weight of bicarbonate ion. Were this labeled 'as bicarbonate' the number of confused would probably go down to 99% as about one percent, being familiar with the 'as CaCO3' notation would know enough to divide the 'as bicarbonate' number by 61. Thus 30.5 mg/L 'bicarbonate' really means 30.5 mg/L 'as bicarbonate' which really means 30.5/61 = 0.5 mEq/L alkalinity (proton deficit). If you see a negative number, such as your -132, the frustration is going to be higher as you are asking probabky asking yourself 'how the hell can I have a negative amount of an ion?' But what it really means is -132/60 =2.2 mEq/L acidity (proton surfeit).

I recognize that there is a good chance that my explanation has confused you even more. IMO the bicarbonate value in Brun water is, for most people (the exception being the few users who understand the chemistry pretty well) worse than useless as it impairs, rather, then enhances understanding. I would, therefore, suggest (as you have done) that you ignore the bicarbonate number and focus on the target pH.

 

[mabrungard]

A negative bicarbonate value has no impact on the validity of the pH prediction. The bicarbonate value is merely a placeholder for the surfeit or deficit of alkalinity in the mash. Once a Bru'n Water understands that the negative bicarbonate value has no effect on their use of the program, 100.00000% of the users have no difficulty with it.

 

[xpops]

Thanks AJ and Martin - I appreciate it and hopefully others do as well! Both explanations make sense and clarify things up....I indeed was wondering how the hell I could have a negative value. I'll continue to focus on pH value rather than bicarbonate value!

Cheers,

 

[ajdelange]

So we can at least agree it's useless. Why not, then, take it out? You will confuse no one if you do that I and won't have to write this explanation over and over again (perhaps I should put it in a Sticky). Of course it seems to me that it would make more sense to turn it into something useful by having this field display the proton deficit/surfeit labeled as such in mEq. I find that when planning a mash it is extremely informative to see the proton deficits and surfeits of each of the mash components laid out on the page before you. Helps the user in deciding what to tweak to hit the target.

 

[mabrungard]

So we can at least agree it's useless. Why not, then, take it out?

Agreed. I've toyed with that thought in the past, since its not really germane to imparting flavor in beer.

However, I like seeing that summary that that sort of serves as a surrogate for the proton surfeit and deficit. But I concede that there are other proton sources in the mash (and in the background of Bru'n Water) that don't show up in that bicarbonate tally. So maybe it is time to retire that component from the display.