Taking PH readings.

[RustyHorn]

The thing I don't understand:
PH readings need to be taken when the wort has cooled, and the reason we adjust the PH is to reduce the amount of bad stuff we extract while mashing (I could be wrong here). The mash converts the starch to sugar within the first 20ish minutes; surely, if the PH is not right, by the time you've cooled a sample then adjusted the PH and cooled that sample to check it's now correct, wouldn't the damage already be done?
A simple explanation would be much appreciated!

 

[logdrum]

I've never adjusted my mash pH based on my readings-I use the data to correct future batches. If it is way too high, I might acidify the sparge a bit more to correct for kettle pH

 

[BeerMakesPeopleHappy]

PH is measured at room temperature to avoid incorrect readings or damage to the meter's probe. The bad stuff (tannins) we extract usually happens during the sparge when the PH of the mash rises too high. Depending on the type of water you are using, the mash PH will usually take care of itself. Otherwise, there are all sorts of calculators you can use on line that work great for getting a general idea of where your PH will be at.

Here's a great article on how PH affects brewing:
http://braukaiser.com/wiki/index.php?title=How_pH_affects_brewing

Honestly, I'd recommend reading everything by Braukaiser if you want to gain a better understanding of the science of brewing.

 

[IslandLizard]

You perform a test mash with say a pound (or even less) of your grist mix, and calculated brewing salt and acid additions in your water (e.g., bru'nwater). You test pH after 20 and 40 minutes. You only need about an ounce of wort, which cools fast in a chilled or frozen shot glass. Make corrections to your water and mash the whole lot. Take a sample at 20' and retest. It should be spot on or close enough. Make notes for next time.

You can add that test mash toward the end, so no grain and wort is wasted.

 

[JLump]

Here's a great article on how PH affects brewing:
http://braukaiser.com/wiki/index.php?title=How_pH_affects_brewing

Wow, what a great source!

 

[RustyHorn]

PH is measured at room temperature to avoid incorrect readings or damage to the meter's probe. The bad stuff (tannins) we extract usually happens during the sparge when the PH of the mash rises too high. Depending on the type of water you are using, the mash PH will usually take care of itself. Otherwise, there are all sorts of calculators you can use on line that work great for getting a general idea of where your PH will be at.

Here's a great article on how PH affects brewing:
http://braukaiser.com/wiki/index.php?title=How_pH_affects_brewing

Honestly, I'd recommend reading everything by Braukaiser if you want to gain a better understanding of the science of brewing.

I use EZ water spreadsheet already. My question was more about adjusting the PH during the mash. Thank you for the link, I'll have a look

 

[RustyHorn]

You perform a test mash with say a pound (or even less) of your grist mix, and calculated brewing salt and acid additions in your water (e.g., bru'nwater). You test pH after 20 and 40 minutes. You only need about an ounce of wort, which cools fast in a chilled or frozen shot glass. Make corrections to your water and mash the whole lot. Take a sample at 20' and retest. It should be spot on or close enough. Make notes for next time.

You can add that test mash toward the end, so no grain and wort is wasted.

That's a great idea. I almost feel silly for not thinking of that myself! Thank you