Controlling mash pH

[beerboymark]

So given that water pre treatment can be a minefield if you can't trust your water report I was wondering whether adding acids or bases direct to your mash after the natural pH has stabilised is a good idea?

My plan:

1. Start mash as normal with no water treatment (apart from campden tab).
2. Wait 10 mins for mash pH to stabilise and check pH.
3. If necessary, treat mash with calculated quantity of CRS to reduce mash pH to desired level.

Brupaks website states you should leave treated liquor a few minutes to dissipate CO2 before using. Would this be an issue if CO2 got trapped in the mash?

 

[Brew_Mike]

No, Make a note of the treatment you used, the pH obtained, and adjust it appropriately the next time you brew. Adding acids and alkalis to teh mash will end up with you chasing your tail in circles too low, too high too low too high . . . get the picture

If you measure the alkalinity of the water you are brewing with you can adjust it appropriately to suit the style of beer you are brewing, and the mash pH will fall in the right range.

 

[beerboymark]

I think you're right there, BrewMike. I can see a right wild goose chase on the cards. I guess the best way is just take note and adjust accordingly for the next time. Or maybe, given the low cost of grain, perform a 1-2 litre mash to check where the pH ends up. Then you know if your water needs adjusting for the main mash.

As for treating to reduce measured alkalinity would you not need to take into account the buffering power of Ca and Mg in your water too? Correct mash pH for pale ales can still be achieved with water high in total alkalinity if there is sufficient Ca and/or Mg.

 

[Brew_Mike]

I think you're right there, BrewMike. I can see a right wild goose chase on the cards. I guess the best way is just take note and adjust accordingly for the next time. Or maybe, given the low cost of grain, perform a 1-2 litre mash to check where the pH ends up. Then you know if your water needs adjusting for the main mash.

Or do several mashes with 100g of your grist with different alkalinities, and see which one has the mash pH you are looking for, after all you only need to mash them for 15 minutes, so it doesn't take a long time. Half a dozen 500ml beakers, and an oven set to 154F.

As for treating to reduce measured alkalinity would you not need to take into account the buffering power of Ca and Mg in your water too? Correct mash pH for pale ales can still be achieved with water high in total alkalinity if there is sufficient Ca and/or Mg.

That is why Burton brewed such great beers, having said that there is a lot of evidence that the water at Burton was boiled to reduce the alkalinity (temporary hardness) before using it to brew the great pales they did. I used to follow the advice of my fellow US brewers on water treatment, who rely a lot on the concept of "residual alkalinity", and I'm not convinced it's correct, I've certainly brewed better British styles since ignoring it, and a lot of my other beers have improved as well.

 

[dan125]

I'm by no means an expert, but I think you're right not to trust your water report, as I think it gives a yearly average and the water supply can vary throughout the year quite a bit depending on where you live.
You can buy an alkalinity test kit quite cheaply though - I live in a high alkalinity area and have noticed a considerable improvement in my beers, since dosing the liquor with the right amount of acid, based on test kit results.
I tend to use half as much acid for dark beers as pales though.