High Bicarbonate Water and pH

[jtdrowns]

Hey all, got some questions/thoughts.

So, I got some left over grains that I plan on putting together to brew up a strong dark Belgian ale. When looking at possible water profiles, I thought Rochefort's would be good. So I plugged in my water, recipe, and salt additions into bru'n water, and to my surprise it estimated my mash pH at 5.9. I believe this is because Rochefort's water profile is so high in bicarbonates.

I could add lactic acid to help reduce the pH, but this will also lower the bicarbonates, and therefore I would not be close to Rochefort's water profile.

Then that got me thinking, how does Rochefort and other high carbonate water profiles even achieve an acceptable mash pH (5.1-5.5)? Or do they just mash with a high pH?

I assume the bicarbonates are not that important when compared to other minerals (sulfate, calcium, etc), and their primary goal is to increase the pH? If so, I should not be trying to achieve the Rochefort bicarbonates amount in my water, but instead make sure my mash pH is in the appropriate area?

What do you all think? Thanks.

 

[ajdelange]

So, I got some left over grains that I plan on putting together to brew up a strong dark Belgian ale. When looking at possible water profiles, I thought Rochefort's would be good. So I plugged in my water, recipe, and salt additions into bru'n water, and to my surprise it estimated my mash pH at 5.9. I believe this is because Rochefort's water profile is so high in bicarbonates.

Yes, if you have high bicarbonate content protons will be absorbed and mash pH will go high.

I could add lactic acid to help reduce the pH, but this will also lower the bicarbonates, and therefore I would not be close to Rochefort's water profile.

True but you would be close to what Rochefort's water profile is after they have treated it to deal with their high bicarbonate assuming they add acid and also use lactic. This is a bit of a stretch but you can assume that they do something to take care of the bicarbonate because they don't want high mash pH anymore than you do.

Then that got me thinking, how does Rochefort and other high carbonate water profiles even achieve an acceptable mash pH (5.1-5.5)? Or do they just mash with a high pH?

They do something to remove the bicarbonate or at least most breweries in similar circumstances do. I don't ,of course, have any idea as to what they actually do at Rochefort but odds are that they take the bicarbonate out. You effectively do that by not putting it in.

I assume the bicarbonates are not that important when compared to other minerals (sulfate, calcium, etc), and their primary goal is to increase the pH?

If you ascribe evil intent to bicarbonate then yes, it strives to increase mash pH. In fact it has no intent. If it is in the water it is in the water and must be neutralized or removed to prevent it from increasing mash pH.

If so, I should not be trying to achieve the Rochefort bicarbonates amount in my water, but instead make sure my mash pH is in the appropriate area?

That's correct. Never add bicarbonate (or another alkali) to your brewing water or mash unless you have verified that your mash pH will go to low if you don't. When all is said and done if the mash pH is correct there will be little bicarbonate remaining. Whether it's not there because you didn't put it into the water or because you did and took it back out (a waste of time) doesn't matter. It can't be in there.

 

[jtdrowns]

Thanks.

I modified the salts to achieve close to the Rochefort's calcium, magnesium, sodium, sulfate, and chloride amounts. I did have to add some chalk to increase the calcium without increasing the sulfate (as gypsum would) or chloride (as calcium chloride would). This did increase the bicarbonates, though I will be adding enough lactic acid to pretty much bring them down to around my original level. The estimated pH is now 5.4.

 

[ajdelange]

Well you increased the calcium lactate. Don't worry about adhering to a profile. Nature usually works logarithmically so that you are more concerned that the concentration of an ion is from 1/2 to twice what the profile suggests than that you be within 1% of it. In fact you can be pretty assured of a decent beer just by adding some calcium chloride (see the Primer) and perhaps gypsum to RO water and not worrying the details beyond that. You can tweak mineral additions to fine tune the beer after you have brewed it with the Primer recommended amounts.

In general, adding a base and then undoing its detrimental effects by using an acid is not productive as calcium lactate is strongly flavored. Calcium phosphate is much more neutral so that if you feel you must have more calcium without increasing chloride or sulfate lime and phosphoric acid would be a better way to go. But don't think you need to add extra calcium to lower mash pH. It is pretty inefficient at that. A much better route for mash pH control is phosphoric acid by itself. It is flavor neutral. If some lactic quality is desired you can use lactic acid instead.

Judging from the questions I think you may be trying to over-engineer this. Check out the Primer.

 

[jtdrowns]

Wow man, thanks. I am kinda over engineering this. This is only my third or forth beer that I have tried to treat the water. So right now, I am kinda dependent on Bru'n Water to guide me along. I got a lot of more research ahead.

That being said, my tap water is RO, and thus is pretty soft:
Ca: 10.4
Mg: 1
Na: 7.9
SO4: 0
Cl: 30
HCO3: 70.7

As you can see my calcium level is low. And I am trying to get a 2:1 sulfate to chloride ratio. For the acid, all I have is lactic as my LHBS does not sale phosphoric. What would you suggest?

 

[ajdelange]

That being said, my tap water is RO, and thus is pretty soft:
Ca: 10.4
Mg: 1
Na: 7.9
SO4: 0
Cl: 30
HCO3: 70.7

If that is RO water the RO membrane needs to be replaced. Your RO system should reject at least 95% of every ion when new. Unless your source water bicarbonate is 1400 it is not doing that.

My standard recommendation for water with the characteristics posted is to dilute 1:1 or 2:1 with low ion (RO or DI) water to knock that alkalinity out, add 1/2 to 1 tsp of calcium chloride to the mix and brew the beer. When the beer is ready to taste do so with small additions of gypsum to the beer in order to see if you think sulfate improves the taste. If it does, then add some gypsum to the water next time you brew this beer and repeat. Fiddle with the amounts of chloride and gypsum added until you hit the sweet spot.

Assuming the beer is to be quite dark you can skip acid additions but it would really be best to check mash pH with a good meter.

 

[jtdrowns]

I never thought about diluting the water with distilled water to reduce the bicarbonates. This helps a lot. I will definitely do that for this batch and future batches. I had to add lactic acid to all of my previous batches in order to achieve an good pH. Though, I have never treated water for a truly dark stout or porter yet.

Yeah, my county has a RO plant. They actually have to add some untreated well water to the treated water to give it some minerals so the water doesn't screw up the pipes.

Thanks again.

 

[mabrungard]

I never thought about diluting the water with distilled water to reduce the bicarbonates. This helps a lot. I will definitely do that for this batch and future batches. I had to add lactic acid to all of my previous batches in order to achieve an good pH. Though, I have never treated water for a truly dark stout or porter yet.

Yeah, my county has a RO plant. They actually have to add some untreated well water to the treated water to give it some minerals so the water doesn't screw up the pipes.

Thanks again.

That is a common approach for utilities that produce RO water. Blend some raw water with the RO water to reduce the corrosiveness of the water. The blended water is still better than the raw water quality and the pipes are more protected. My community performs ion-exchange on the tap water and blends raw water to also reduce its corrosiveness.

A more modern approach to reducing ionic content is to use more permeable membranes that reduce less of the ionic content with a substantial reduction in their treatment cost. These membrane-softening systems utilize nanofiltration membranes instead of reverse osmosis membranes. I would not be surprised if the system above used such a system. Pure RO water is not ideal for municipal water systems (nor brewing water in many cases). Many large breweries utilize nanofiltration due to its lower cost of production and desirable, modest ionic content.