All Grain Stout with Soft Water

[prjectmayhem]

So I am wanting to brew a coffee stout with my water here in SF which is very low in alkalinity (30 ppm CO3 from water report) with a pH of about 8 out of the tap.

In the past I have been able to balance pH with a little bit of sodium bicarbonate, but for this recipe I want to use calcium carbonate. I am aware of its incredibly poor solubility in water, but is there any benefit to stirring it into the mash? Would the acidic mash water solubalize the CaCO3 enough to make a significant change or would there be solid chalk floating around in the mash? Anyone ever try adjusting alkalinity this way, or just I just go back to my baking soda addition and bite the bullet for having extra sodium?

Secondly, is there any real use for calcium carbonate in home brewing if it is so insoluble?

 

[treebeerd]

The only way I know of to make calcium carbonate more soluble is to carbonate it. Pickling lime is another option to lower ph that would probably have less effect on flavor than sodium bicarbonate.

 

[AZCoolerBrewer]

Isn't 8 highly alkaline already? Wouldn't adding baking soda make it more alkaline yet? Is that right for a stout? I know nothing about water chemistry as it relates to brewing, but am interested in learning about it.

 

[BlueHouseBrewhaus]

The only way I know of to make calcium carbonate more soluble is to carbonate it. Pickling lime is another option to lower ph that would probably have less effect on flavor than sodium bicarbonate.

+1 on pickling lime. It's soluble, works great, doesn't add off flavors and boosts your Ca for healthy fermentation.

Isn't 8 highly alkaline already? Wouldn't adding baking soda make it more alkaline yet? Is that right for a stout? I know nothing about water chemistry as it relates to brewing, but am interested in learning about it.

The pH is on the high side but with such soft water, the dark grains will pull it down fast. Some adjustment will still likely be necessary.

OP, plug your water and grain bill into Brunwater or another water chemistry program and it will tell you just what you need. You might also want to post this in the Brew Science forum. AJ and Martin can answer pretty much any question you can think of plus the ones you can't think of.

 

[prjectmayhem]

Isn't 8 highly alkaline already? Wouldn't adding baking soda make it more alkaline yet? Is that right for a stout? I know nothing about water chemistry as it relates to brewing, but am interested in learning about it.

You are right, the water is already alkaline but it is so soft that the pH of the grains drops it to around 5.0 with this kind of grain bill.

 

[prjectmayhem]

+1 on pickling lime. It's soluble, works great, doesn't add off flavors and boosts your Ca for healthy fermentation.




The pH is on the high side but with such soft water, the dark grains will pull it down fast. Some adjustment will still likely be necessary.

OP, plug your water and grain bill into Brunwater or another water chemistry program and it will tell you just what you need. You might also want to post this in the Brew Science forum. AJ and Martin can answer pretty much any question you can think of plus the ones you can't think of.

Yeah I plugged this into my beersmith water calculator and that's where i got the need for ~2.6 g of CaCO3, and that is the source of my question/confusion. Thanks for the tip, I'll jump over to brew science!

 

[specharka]

So I am wanting to brew a coffee stout with my water here in SF which is very low in alkalinity (30 ppm CO3 from water report) with a pH of about 8 out of the tap.



In the past I have been able to balance pH with a little bit of sodium bicarbonate, but for this recipe I want to use calcium carbonate. I am aware of its incredibly poor solubility in water, but is there any benefit to stirring it into the mash? Would the acidic mash water solubalize the CaCO3 enough to make a significant change or would there be solid chalk floating around in the mash? Anyone ever try adjusting alkalinity this way, or just I just go back to my baking soda addition and bite the bullet for having extra sodium?



Secondly, is there any real use for calcium carbonate in home brewing if it is so insoluble?

Yes, CaCO3 does work. It just doesn't dissolve into water that is already high in cations. Once the grain is mashed, the pH will drop enough for the rest of the chalk to dissolve. You just need to stir the mash to evenly distribute it.

I wouldn't recommend using chalk or pickling lime in sparge water, though. That's just asking for tannin extraction.

 

[mabrungard]

pH and alkalinity are not the same. Water can have a fairly high pH and still have alkalinity near zero and vice versa.

For brewing most stouts and porters with low alkalinity water, adding alkalinity to the mashing water will improve the taste and perception of the resulting beer. However, using chalk is not a suitable alternative since it does not dissolve in a significant way...even in the presence of the mash acids. The acids found naturally in the mash, are not strong enough to dissolve chalk. In general, the mash pH will rise a maximum of about 0.1 units, no matter how much chalk you add. That is not a reliable method of keeping your mash pH up in the desired range.

Better options for adding alkalinity are lime and baking soda. Lime is good, but its strength can decrease with time and exposure to atmospheric moisture. Baking soda is a more consistent option for adding alkalinity. While it does add sodium to the wort, the actual contribution is typically modest since the sparging water doesn't need baking soda and that sparging water will dilute the overall sodium content. The typical overall sodium content in the finished wort is only on the order of 40 ppm and that level is actually an enhancement in roasty beers. So, baking soda is a very good option for keeping mashing pH from dropping too low.