How long to wait after mash adjustment

[MI_Troll]

1) How long should I wait after making a mash pH adjustment before I measure again, assuming a good stir after adjustments have been made?

2) In the event of an overshoot of said adjustment, should I try to bring it back the other way or is the prospect f having to re-correct the other way and still missing the target not worth the risk of adding a ton of stuff to your mash you don't really want there?

I'm leaning towards 1 adjustment (in this particular incident 1ml lactic acid) and live with it, but I can't help but want to throw in some uppers to counteract the downers.

Talk me off or over the ledge, thanks!

 

[ajdelange]

I'd say start right away but keep taking measurements as fast as you can. You will, with experience, be able to tell where pH is going to level off. But of course with experience you will know how much acid to add at the outset and won't be making corrections.

Try very hard not to overshoot. Everyone who owns a pH meter has wound up chasing his tail at least once but if you are careful you may be able to avoid it. If you think you need a mL of acid add half and see what happens. It may take 15 minutes for the reading to stabilize. If you are still way high then add the other half (and try to figure out what went wrong later). If you are a bit high live with it and resolve to do better next time.

 

[WoodlandBrew]

Agreed add less than you think you will need to keep from chasing your tail. I dough in with the salts added, stir for a minute or two until it looks well combined, and then give it a little more to make sure. Then measure pH. If it's between 5.0 and 5.4 I write down what it is and just leave it. If I'm outside then I adjust. The first time I used lactic acid to adjust I added about 10ml to a 3 gallon 7 pound mash. That was WAY too much. In that case I did do a little back and forth.

Using the various spread sheets should give you an idea of the amount of acid that may be needed, but I wouldn't add it until after you have checked the pH.

This equation works for me:

mL acid to add = pounds of grains * pH adjustment needed.

For example if I was mashing 10 pounds of grain and doughed in at 5.6 and I want to be at 5.2, I would add 4mL of acid.

This may or may not work for you, but it might give you an idea.

Here is a blog post about it:
http://woodlandbrew.blogspot.com/2012/10/mash-ph.html

 

[MI_Troll]

Thanks,

Hadn't really planned on brewing again today, but since everything was still set up and my starter was ready I went for it. I again came in higher than ezwater predicted, but this time I added half the lactic acid it said to which turned out just right (5.5pH).

To that end, ezwater always gave me spot on predictions in previous batches and I never had to make adjustments, the last couple have been off. The difference, which could be a big one, is the water I'm using. I previously used distilled water for all my brews, but have switched to RO because I can get it cheaper. I can't find my TDS meter to compare the two but in talking to the clerk at the store who apparently has a reef aquarium and knows about water testing the store has the proper equipment and maintains their RO system. Should I expect a difference between distilled and RO? I always thought the two were pretty much interchangeable.

 

[afr0byte]

Thanks,

Hadn't really planned on brewing again today, but since everything was still set up and my starter was ready I went for it. I again came in higher than ezwater predicted, but this time I added half the lactic acid it said to which turned out just right (5.5pH).

To that end, ezwater always gave me spot on predictions in previous batches and I never had to make adjustments, the last couple have been off. The difference, which could be a big one, is the water I'm using. I previously used distilled water for all my brews, but have switched to RO because I can get it cheaper. I can't find my TDS meter to compare the two but in talking to the clerk at the store who apparently has a reef aquarium and knows about water testing the store has the proper equipment and maintains their RO system. Should I expect a difference between distilled and RO? I always thought the two were pretty much interchangeable.

Well, certainly RO is going to have higher alkalinity than distilled, so that may be having some effect, but I doubt it's a lot as long as the RO output is decent. Were your recent batches perhaps with a different base malt? The base malt can have a big effect, especially with RO/DI water.

 

[MI_Troll]

The base malt (2-row) were recently bought in bulk, so at least 11 lbs of a 13 lb grain bill all came from the same bag. The other malts were munich and crystal 60 at a pound each purchased at different times. I wouldn't think at that volumes those would be the culprit.

 

[ajdelange]

Should I expect a difference between distilled and RO?

No. Distilled water has an alkalinity of about 2.5 and RO water perhaps twice this depending on whether the system is up to snuff and on what the alkalinity of the incoming water is. If it's 80 and the rejection is 98% you'll have about 3.5 for the alkalinity whereas if the feedwater has an alkalinity of 300 and the rejection has dropped to 95% then you'd have about 17 - 18 alkalinity in the permeate. Even this much wouldn't pull mash pH very much.

Another possibility is that the RO supplier adds some salts to the water to make it more palatable. I understand that some do this. If they have added bicarbonate in appreciable quantity then you might expect a difference. I'd ask about this at the store where you get the water (or, as you noted a TDS check would be revealing).