Bicarbonate reduction - PH

[vanala]

Hi,

I live in Munich and we do have pretty hard water dH/KH 16/15 - HCO3 320 mg/l, so I started to treat water with lime using braukaiser xls sheet (LINK) and franklinbrew method (LINK).
I yet to have to taste the brews as they are fermenting/maturing but would like to ask about pH after reduction.

I do brew everything but trying to do some good basic Pale Ale and so far I think because of the bicarbs they are coming out a little bit harsh tasting... So my goal is to reduce bicarbonates to close to zero and then pump it up as needed.

I am treating 25L of water (doing 1/2 brew) with this profile
pH 7,6
calcium 80,0
Mg 20,0
sodium 4,0
sulfate 15,0
chloride 9,0
bicarb 320,0
alkalinity 268,8

Calculations recommend around 5g of lime [Ca(OH)2)] + some extra Calcium to aid the reaction
I did 3 different runs adding

for the first one 5g gypsum (CaSO4·2H2O) 3g of Calcium Chloride (CaCl2) and 5g of lime the result was (dH/KH measured, rest calculations only):

dH/KH 18/2
pH 9,2
95,2 Ca mg/l
20,0 Mg mg/l
4,0 Na mg/l
126,6 SO4 mg/l
66,9 Cl mg/l
43,4 HCO3 mg/l
35,6 as CaCO3

I thought good enough maybe too much Ca and pH little bit too high so for the second time I went with 5g gypsum, 1g Calcium Chloride and 4g of lime :

dH/KH 14/5
pH 8,5
66,7 Ca mg/l
20,0 Mg mg/l
4,0 Na mg/l
126,6 SO4 mg/l
28,3 Cl mg/l
97,7 HCO3 mg/l
80,1 as CaCO3

this one ended a little bit too high with bicarbonates so I went back with 5g of lime 5g gypsum and no Calcium chloride:

dH/KH 8/1
pH 9,5
24,0 Ca mg/l
20,0 Mg mg/l
4,0 Na mg/l
126,6 SO4 mg/l
9,0 Cl mg/l
32,6 HCO3 mg/l
26,7 as CaCO3

very close to my goal but I am a bit worried about the pH being a little bit too high, I have measured mash pH and in all cases it was between 5,2 - 5,4, mashing efficiency was 70+ and I used only slightly modified grains (carabelge/carahell) accounting for less than 15%.

Question - what do you think about treated water profile as a base water and should I be worried about high pH?

Thanks!

 

[Hermit]

Have you read the primer stickied to the top of this forum?
https://www.homebrewtalk.com/f128/brewing-water-chemistry-primer-198460/
Excellent place to start.

 

[FourSeasonAngler]

If you think you would benefit from a lower starting pH maybe a bit of Lactic Acid is in order before you mash in?

Honestly though this is just a stab in the dark, I really want to hear what AJ and Martin have to say.

 

[mabrungard]

Ah, Munich water. Ideal for lime softening and many breweries in Bavaria do use it.

In the case of the lime-softened water, the relative lack of calcium in the tap water is the limiting factor in how low you can get the alkalinity. In other words, there isn't enough calcium to pair up with the carbonate to create the chalk precipitate. This results in the treated water having a somewhat high alkalinity that cannot be further reduced with this method.

In your case, you would still have to employ an external acid to neutralize that excess alkalinity. You can do it the traditional German way and use acid malt or you could employ a liquid acid. The remaining alkalinity is not really high enough for most drinkers to taste the lactate ion content if acid malt or lactic acid was used. However in the case of pale ale brewing, you may want to use sulfuric acid since you can benefit from the resulting elevated sulfate content in the brewing water.

You are on the right track regarding the need to reduce the bicarbonate content, it is just that you do have to employ the external acid.

 

[vanala]

Great thanks! I will try more gypsum first, and order some Saurmalz next. Will post results...

 

[ajdelange]

I am treating 25L of water (doing 1/2 brew) with this profile
pH 7,6
calcium 80,0
Mg 20,0
sodium 4,0
sulfate 15,0
chloride 9,0
bicarb 320,0
alkalinity 268,8

So you have 4 mval calcium and 5.37 of alkalinity. The rule of thumb says that you should be able to drop down to 1 mval of the lesser which implies here that you should be able to remove 3 mval each of calcium and alkalinity.

Calculations recommend around 5g of lime [Ca(OH)2)] + some extra Calcium to aid the reaction
I did 3 different runs adding

for the first one 5g gypsum (CaSO4·2H2O) 3g of Calcium Chloride (CaCl2) and 5g of lime the result was (dH/KH measured, rest calculations only):

dH/KH 18/2
pH 9,2
95,2 Ca mg/l
20,0 Mg mg/l
4,0 Na mg/l
126,6 SO4 mg/l
66,9 Cl mg/l
43,4 HCO3 mg/l
35,6 as CaCO3

2° KH = 35.6 ppm as CaCO3 so you got the alkalinity below 1 mval. Victory!

I thought good enough maybe too much Ca and pH little bit too high...

Not so bad but if you want less...

so for the second time I went with 5g gypsum, 1g Calcium Chloride and 4g of lime :

...

this one ended a little bit too high with bicarbonates so I went back with 5g of lime 5g gypsum and no Calcium chloride:

dH/KH 8/1
pH 9,5
24,0 Ca mg/l
20,0 Mg mg/l
4,0 Na mg/l
126,6 SO4 mg/l
9,0 Cl mg/l
32,6 HCO3 mg/l
26,7 as CaCO3

very close to my goal but I am a bit worried about the pH being a little bit too high,

No matter as there is little alkalinity to 'back up' the high pH. Think of it like this: a voltage of 1.5 V from a hearing aid battery is of less consequence that 1.5 volts from a cell in a battery bank used to start a diesel locomotive. The proof that this higher pH is inconsequential is....

I have measured mash pH and in all cases it was between 5,2 - 5,4,

Question - what do you think about treated water profile as a base water

More sulfate than I like in my beers (I'd get the extra calcium from CaCl2 and skip the gypsum) but that's a matter of taste.

..and should I be worried about high pH?

No. Definitely not. You have described successful lime softening.

In your case, you would still have to employ an external acid to neutralize that excess alkalinity.

This seems to imply that you have not. You have. Were you to mash 7 kg of Weyermanns Pils with 1 kg of their 60L in 20 L of water and wanted a pH of 5.4 you would need 25 mEq of additional acid. Only 9 of those would go to the water, the other 16 to the Pils malt (the caramel would supply 47). The base malt needs 69. So it is really the malts that are controlling things at this point. Not the water.