Mash pH and Building Up RO Water

[Jimbob]

I've been using RO water for sometime now because of the quality of water in the area I'm in and the beers I've been brewing. After running some numbers it seemed easier to build up RO Water rather than dilute my tap water. Further even after filtering the water it still has an odd taste and smell that I don't want to use it in my beer. I've been using John Palmer's water calculation spread sheet from his web site. I've been pretty content up to this point sticking with what I calculate and learning what needs to be added and how the different salts interact and affect the water profile. The problem I'm having however is not getting the mash pH down in the 5.2 range. I've been hitting about 5.5 to 5.8 on most of my batches. So I'm usually pretty high.

I've got 5Star's 5.2 but I haven't really used it because I would like to learn how to dial this in and I don't know exactly what I'm putting into my beer. I can add additional salts to adjust the pH but this then throws my residual alkalinity out of wack. I know building up water with salts is kind of a hand waving exercise but I'm wondering first what I should do to get my pH down and how I keep my new water profile in balance as I originally designed it? Or how much of and what should I be willing to compromise to achieve a 5.2 pH?

Further, what and how much should I use to make my pH adjustments during the mash? For example, if I add 2 grams (half a teaspoon) of gypsum what effects can I expect? A 0.1 PH drop? (just an example) Does anyone have any "rules of thumb" for this?

[uncle_bad_touches]

if you have the mineral profile you want and still need to drop your pH further I would use either lactic or phosphoric acid. you could also use acidualted malt or additional darker grains, however that would throw off you RA.

I don't know of a good way to calculate pH adjustments. and the mash pH won't drop off in a linear fashion when adding acids. the buffers present will "absorb" the acid additions until their buffering capacity has been exceeded, and then the pH will begin to drop rapidly. best bet is to add 1-2 ml of acid, measure pH, lather, rinse, repeat.

[11amas]

First off, there are threads on building RO water, read what AJ has to say and you won't go wrong. Just do a search for building RO water. Second, are you measuring your mash pH? Don't even consider tweaking your pH until you know you actually need to. When I measure I usually have a pH between 5 and 5.4. Why dump a bunch of stuff in your mash that has nothing in and of itself to contribute to your beer unless you know there is a need?

Read this and you should be able to come up with more detailed questions.

Honestly, I have been trying to adjust water less and less; if I have 50-100ppm Ca and some nutrients I ask myself why I need much more. Add some gypsum and you have a good dose of SO4...ok, tweak the SO4 Cl balance a bit based on hoppy vs. "round" taste but that is after you have the basics together.

[Jimbob]

I don't know of a good way to calculate pH adjustments. and the mash pH won't drop off in a linear fashion when adding acids. the buffers present will "absorb" the acid additions until their buffering capacity has been exceeded, and then the pH will begin to drop rapidly. best bet is to add 1-2 ml of acid, measure pH, lather, rinse, repeat.

Thanks uncle_bad_touches I haven't looked into using acids in the mash. I will do some reading on that thanks!!!!

11amas, I do have a pH meter. I feel pretty confident on building up the water profiles and have done quite a bit of reading on building up from RO but I haven't really found how to dial it in to get the right mash pH. Like I said I understand that this is a bit of a hand waving exercise. I'm just wanting to get a bit more dialed at the same time keeping my water profile appropriate for the style.

[Datamike]

I think you may be going about this somewhat backwards.

You should be concerned with the proper mash PH first, then worry about style profiles and sulfate/chloride ratios. If you're consistently high on your mash PH, then you're calculating wrong or using bad data.

RO water is not all the same. You should have it tested to see what's in YOUR RO water. RO filters are great for removing most things; not so great for others, such as sodium.

Michael

[Jimbob]

I think you may be going about this somewhat backwards.

You should be concerned with the proper mash PH first, then worry about style profiles and sulfate/chloride ratios. If you're consistently high on your mash PH, then you're calculating wrong or using bad data.

RO water is not all the same. You should have it tested to see what's in YOUR RO water. RO filters are great for removing most things; not so great for others, such as sodium.

Michael

I agree that the pH should be a concern but there is no way to estimate you pH when calculating the water profile that you are building. RA is the prime indicator for what you want. I feel pretty confident with what I've done so far, of course I could post some of my profiles and and be told that I am way off. However my I've been designing the RA of the water to meet the requirements of the beer style.

I also agree that all RO water is not the same. I have sent samples of the RO water that I purchase from a vendor in my area. So I know what that profile is.

[ajdelange]

I agree that the pH should be a concern but there is no way to estimate you pH when calculating the water profile that you are building.

You can estimate how much the pH will be expected to shift relative to a DI water base malt mash, most such mashes come in at 5.7 - 5.75. The shift is 0.00168 pH per unit of RA expressed as ppm as CaCO3.

RA is the prime indicator for what you want.

Not really. RA is a way of comparing water sources and giving rough indications of what you may need to do to them depending on the style of beer to be brewed. The Ca/PO4 reactions quantified, to some extent, by the RA can only take you so far. It is more likely that mash pH will be set by added acids either in the form of dark malts, acidulated malt or acid from a bottle.

I feel pretty confident with what I've done so far, of course I could post some of my profiles and and be told that I am way off. However my I've been designing the RA of the water to meet the requirements of the beer style.

There is a rough correlation between the RA of the water used to brew a style and the style's depth of color (SRM or EBC) but styles do not have RA requirements. If someone tells you that you "need" an RA of 500 to brew a stout (and I've seen such things posted) ignore that person. In general you should design the water to have the general characteristics of the water of the region in which the style originated (e.g. Irish stout ~ hard, high carbonate RA 50 - 150; Boh. Pils ~ very soft; Helles ~ high carbonate hardness but otherwise low mineral content; Burton ales ~ lots of sulfate hardness...) and then do whatever you need to do to get the mash pH right doing it, where possible, the way the original brewers of the style did it (Irish Stout ~ roasted barley; Pils ~ sauermalz; Helles ~ decarbonation, sauermalz; Burton ales ~ do nothing). If you approach it this way you will get something that is highly authentic but not necessarily the "best" beer. You can use this "authentic" method as a way to get to a starting point for recipe development.

The proof of the pudding is in attaining a proper mash pH. If you have a meter, use it but be sure you know how (calibration), understand its quirks and so on. With decent meters avaialable now for $90 a pH meter should (IMO) be part of every serious all grain brewers kit. As experience is gained it should be possible to put the pH meter aside by which I mean that if you brew the same beer to the same recipe using the same water treatement 10 times in a row and get a proper mash pH 10 times in a row you shouldn't have to do a check on the 11th. OTOH the pH drop that comes in the first few hours of a healthy fermentation is always a comforting assurance that the fermentation is off to a good start.

I also agree that all RO water is not the same. I have sent samples of the RO water that I purchase from a vendor in my area. So I know what that profile is.

Certainly the profile of the RO water used for synthesis has some effect on overall qualties of water built up from it but as RO units are effective in removing most of most ions (i.e. 90% or more) the actual ion content should not be that significant unless the water is really loaded before passing through the RO unit or you are designing soft waters (e.g. for a Boh. Pils or Helles). Most RO units sold have specs on how much of what they take out and you ought to be able to get a decent idea of what your RO output profile is by applying those numbers to the analysis of the input water.