Couple of questions on water

[Romex2121]

I was reading a few different articles on the net on building up RO water for brewing ,
I don’t remember who wrote the article but he recommended building your water a day or two before brew day so any changes to the water could be made to get the PH level where you want it before it was to late ,,,,
If you set up your brew water (RO) prior to brew day let’s say to a PH of 5.3 and then on brew day added your grains to the pre built mash water wouldn’t the PH change due to whatever grains your using ??
It didn’t sound like the article was trying to build a water specific to a certain region so I’m assuming they were not ......

 

[day_trippr]

Don't forget, the goal is to tune the brewing liquor to account for the net content of the mash - grains plus water - to arrive at a prescribed pH level. Strike water for a light color beer (say SRM 3-4) is going to be well below pH 5.3 prior to the actual strike - closer to the low 4.somethings in fact.

Anyway...I rely on software (Bru'n Water) to take my raw water input (RO in this case) plus grain types and weights plus my chosen water profile to tell me what needs to go in the brew day's water. I run my RO system to produce typically 20 gallons (takes a little under 5 hours) the evening before a brew day, mix in salts and acids as needed brew day morning, and I check the mash pH and boil kettle pH and record them for the next time I brew that recipe. If adjustments are desired, they go in the next batch and the results are, again, recorded.

Eventually that recipe is dialed in for posterity. I can say within styles I can share water construction across numerous recipes - nearly all of my neipas use the same water construction.

One thing about letting water sit around for a couple day: the pH will steadily drop due to CO2 absorption. If RO water, it'll drop quite quickly. That might introduce a complication...

Cheers!

 

[VikeMan]

I was reading a few different articles on the net on building up RO water for brewing ,
I don’t remember who wrote the article but he recommended building your water a day or two before brew day so any changes to the water could be made to get the PH level where you want it before it was to late ,,,,

Whoever wrote that article is nutz.

If you set up your brew water (RO) prior to brew day let’s say to a PH of 5.3 and then on brew day added your grains to the pre built mash water wouldn’t the PH change due to whatever grains your using ??

Definitely. The mash pH is the thing to target, not the water's pH, which is nearly meaningless. The alkalinity of the water matters a lot, which is why you tell your mash pH software what the alkalinity is.

Strike water for a light color beer (say SRM 3-4) is going to be well below pH 5.3 prior to the actual strike - closer to the low 4.somethings in fact.

This can be quite true, if the method of acidifying the mash is the addition of lactic/phosophoric acid. If the acidification is done by adding calcium salts, they don't do anything to the pH of the water (without grains), because they have to react with phosphates from the grains to reduce the mash pH.

 

[Bramling Cross]

Due to working a pandemic night shift, I've introduced some new steps to my process to streamline my brew days. Part of this involves measuring and building my water (minerals and acid) the night prior to a brew day. The water then sits in the kettle and HLT for 6-9hrs at ambient temperature prior to being heated for mash-in the following morning.

I've been pre-building my water for 14 months and I've noticed no difference in established expectations for mash, pre-boil, and post-boil pHs when compared with my prior brewing records. While this is not a controlled experiment, it seems reasonable that if there was a consistent, measurable difference between pre-built and water built shortly before mash-in, I would've caught it during the past year.

 

[ScrewyBrewer]

As long as you know which grains will be in the recipe, there is nothing to prevent you from adding your brewing water minerals and or acid to the mash water ahead of time. I have been building my brewing water before brewday for years, and it's a good practice to follow.