RO/DI Water and pH readings

Post #1 made 9 years ago
Here is some thing that I posted on another forum which I think could be useful to all.

Since starting to use 100% RO/DI (reverse osmosis de ionised water) water for my brewing (salts added) I have found great improvements with my beer quality. One thing that I and my fellow brewers have found that we were getting great fluctuations in pH measurements of the RO water.

Well today after pondering if all our pH meters were stuffed "Mr X" found this great post below and we are now much relieved .

"The pH of RO/DI water is extremely difficult to measure accurately, as the pH measurement is dependent upon the transport of ions. If you have de-ionized water, there are not enough ions to get an accurate measurement. Standard protocols for measuring pH of deionized water includes adding a neutral salt such as potassium chloride in order to get an accurate measurement.

RO/DI water also has no buffering ability. As soon as you add your sea salt mix to it the water will quickly adjust to whatever the native pH of the sea salt mix is.

In other words, don't waste time worrying about the pH of your RO/DI water."

Old brewer new trick's. Just goes to show that there is always some one out there you can learn from. :scratch:

Post #2 made 9 years ago
Welcome to the forum pHman. Great to see you posting here at last :peace:,

Congrats on what is probably the most technically advanced post on this forum to date. I know you can only type with one hand at the moment but I am looking forward to seeing you give us some great chemistry lessons here. You better dumb them down a bit for me though :lol:

Can we start with a few basic questions though before we get into RO/DI's? :scratch: (I think the majority of us here aren't very brewing chemistry savvy!) I can feed them to you one at a time if that helps. It would certainly help us non-chemists!

So, first question...

1. A BIABrewer mashes in full-volume so I always try and get all my water to a pH of about 5.3 before I mash in. I am doing this for all my beers, lagers and ales, and I find the pH doesn't vary much after I add my grain (even for dark beers) probably due to the extra volume of BIAB. Am I getting this right?

Great to have you here,
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Post #3 made 9 years ago
I am not much of a brew chemist either but I have learnt from experience in the brew house. You can read shed loads of stuff about pH but unless you understand the very basics its not easy to convey the harder stuff. So I will not try and do that !
I will ask you a few question first.
Are you using filtered tap water ? if so do you have a ion (salts) profile for your water?
How are measuring your pH ?
Why are you adjusting your mash liquor before proceeding to mash ? I dont see why "full volume" would make this necessary.
What are you using to adjust the mash liquor, acid?
The reason I ask is different acids can taint your wort flavour when used to excess.
I think you need to understand that it is Calcium (AKA brewing salts) in your mash/liquor which is going to adjust the mash pH the most, then if necessary you an adjust with small additions of acids or acidulated malt (Lactic acid).
What you are trying to do with Calcium is for it to react in the mash to lower your pH and also its very vital for yeast growth/health.
So my first recommendation is to not adjust your water till you have taken a mash pH.
Cheers Pman

Post #4 made 9 years ago
My apologies for the slow reply pHman - busy times :dunno:

As for you not being a brew chemist - lol! You are the brew chemist man!

Answers to most of your questions...

1. I am not using filtered water - just Perth tap water.
2. I measure my pH with paper strips but the consistency has been that good that I...
3. Just add 125g of acidulated malt to every batch I brew regardless of whether it is light or dark and it seems to work out at about 5.2 - 5.4 pretty consistently.


1. I never knew that about calcium. (Well, I did, but I never bothered with it ;))
2. I have to admit that I can't taste any difference between say a pale ale that I pH adjust and those that I don't. On the plus side, any beer where I have had an award, I am pretty sure I used acidulated malt.
3. On another plus side, using your recipes, any lager award I have received was using acidulated malt.

Full-Volume Brewing - BIAB

I'm not sure how to answer this as my memory of my experiments is perhaps dubious. I know that the 125 g of acidulated malt gives me a mash pH of say 5.2 - 5.3. My uncertain memory tells me that before you got me onto acidulated malt, I used to use citric acid and that I used to adjust all the hot liquor before adding my grain. Here's where I might be wrong but my memory is telling me that the addition of the grain (light or dark) did not change the pH at all. I suppose this is because, in full-volume brewing, we are using about three times the liquor that traditional brewers use so grain addition becomes a lot less critical???

Another Question

I now believe all brewers have different palates. For example, you and I have had the same beers and some have a small flavour that I can't stand and you don't notice and vice versa.

My suspicion is that some brewers are susceptible to identifying some fault range or combination while others are adept at identifying another range.

Avoiding the possibility of faults is great and I certainly try to do this as much as possible. But, I suspect that a lot of brewers (kit, extract, partial, traditional or BIAB) who brew a shit beer, will, if they are forum-orientated, latch onto the latest thread as being the answer to their problems.

I have certainly done this!

So, what I am wondering is how many new brewers should even worry themselves about pH? Has a crap brew ever been made good simply through a change in pH or has a good brew simply been made a bit better through a change in pH or has a great beer become superb simply through a change in pH?

I'd be really interested in hearing anyone's thoughts on this as I think it will help us all to prioritise when it comes to fault-finding.

Thanks a heap for starting this thread pHman. You've got me thinking!

Last edited by PistolPatch on 02 Jan 2011, 00:37, edited 5 times in total.
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Post #5 made 9 years ago
From personal experience, I guess that pH is just part of the equation. The other mineral concentrations as well as chloride to sulfate have some input on your beer too. For the most part, this is all just making the difference between a great beer and a great beer that wins awards. My own experience is derived from my homebrew club's IPA recipe. We brewed it up with city water at a friend house once and it was fabulous. Then we brewed the same recipe up at my house using my well water (practically distilled/RO water as far as mineral levels) and it was not so fabulous. Still a good beer, but the hops came through a bit muddied. Mind you, these were extract with specialty grains and partial boil of 10 gallons that was diluted out to 20 gallons so the pH part wasn't a factor. Our guess is the minerals and more specifically the chloride to sulfate ratio which for my bare water is good for malty beers....not really good for an IPA. Dark, malty beers without mineral additions were all fine, it was when I went pale and/or hoppy, the beers just weren't "right".

Since this experience I have been playing with mineral additions using the spreadsheet found on that Homebrew forum. But when I started looking at dark, hoppy beers, it seems like way too much salt additions for pH predictions. That's when I ran into that Aussie's paper (due to a kind poster here on BIABrewer) about water very similar to mine and the suggestions in that paper are what I follow now. The only issue I have now is when I want to do a very pale beer, it suggests an acid rest and/or acidulated malt. But how long of a rest is needed? Or, how do you figure out how much acidulated malt to use?

I'd go the route of pH strips but I've failed twice. I ordered some and they just didn't work. I even tried putting them in pickle juice and vinegar and got nor readings (change of color). I complained to the supplier and they sent a new vial...same thing. So I gave up on them. I have been toying with the idea of a pH meter, but don't have the funds and it sounds like a bit of a hassle. All I am looking for now are ball park percentages of acidulated malt to use. I can then use experience to adjust up or down based on taste.

I believe that for most people, if you can drink your water, you can brew good beer with it. But I also believe that people on either end of the spectrum (high mineral or low mineral content) cannot brew all beers with good results, just either dark or light and/or hoppy or malty depending on their mineral levels. Just IMHXO.
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Post #6 made 9 years ago
Two If By Sea wrote:All I am looking for now are ball park percentages of acidulated malt to use. I can then use experience to adjust up or down based on taste.
Here is a great thread about water chemistry and AJ DeLange gives ballpark figures for sauermalz additions for different styles assuming very soft water or RO/distilled water.

I haven't gotten a water report for my area yet, but will probably implement some amount of sauermalz to my next beer.
Last edited by BrickBrewHaus on 02 Jan 2011, 07:27, edited 5 times in total.

Post #8 made 9 years ago
Hi All,

I have never concerned myself too much with mash pH, because I'm happy with the beers being produced. However in the quest to further the experimentation process, and keep the hobby interesting & challenging, in 2011 I am determined to monitor the variances between various grain bills out of general interest. Whether I do anything about it is another story.

One question I have with regards to BIAB, is whether you can assume the same targets as with the rules of mash pH in a conventional setup compared to when doing full-volume brewing.

I would have thought that a water-to-grain ratio of 4L/Kg will present a different mash pH to a 7/1 BIAB ratio, and the relevant figure recalculations should be made to accommodate the different methodology.

Any thoughts on this?

Post #9 made 9 years ago
Yep Ted, sounds fair, the only exception I'd make is that not all BIABs use that 7:1 ratio which assumes mashing and sparging are combined. Maxi-BIAB is a point in case, it uses 4:1 and 2 * 2:1 or something like that depending on how it is sparged. So it is really quite similar to the more conventional mashes, not by design but just by coincidence. I use Maxi-BIAB almost exclusively (I do the odd partial mash now and then), I just love it for being competitive at the state level and also nationally while costing less than two cartons of megaswill to set all the gear up! :smoke:
I've got a few different sorts of pH kit (at work that is) but never really seen the need to measure it as I've been happy enough with the beer, efficiency in particular. I use rainwater and in ales 6- 8g each of CaSO4 and CaCl2, 2- 4g MgSO4, in lagers about half, but will be looking more closely at the proportions this coming year. I doubt my rainwater is squeaky clean, I'm actually not game to analyse it knowing what's in the tank and gutters, but I know it has worked fairly well so far...
Another thing that seems to be overlooked and confuses many (me included) is that there's water adjustments for mash performance (eg. loading up with Ca) and there's adjustment for flavour effect (eg. Plsen, Burton Upon Trent etc. profiles), so you'll see some additions split into mash addition and sparge or kettle addition.
Finally, there's some schools of thought which say the strike water chemistry itself is largely meaningless, but the mash chemistry is critical, which makes sense when you consider that adding kilos of grain to a relatively small amount of water completely overwhelming the few tens of mg/L which comprise the strike water profile. I realise not all of the grain is soluble, otherwise we wouldn't have this thing called mashing.
Hope this helps, will be keenly following any discussions! :drink:
Last edited by Ralph on 03 Jan 2011, 14:30, edited 5 times in total.
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