Low mash pH help

[JonA]

I'm after some help please - as to why my mash pH is coming out low, and what I can do about it.

I've never paid much attention to mash pH before as I only had some cheap and cheerful pH papers which kind of showed it as 'in the ball park' you might say, but in an effort to improve my brewing standard and consistency, I just had my water analysed by Murphys and bought a pH meter.

This is Murphys analysis, which is not far off the water company's data.
pH: 7.1
Nitrate: 23
Calcium: 118
Magnesium: 14
Chloride: 76
Sodium: 61
Sulphate: 109
Alkalinity (CaCO3): 220

They also gave me some recommendations for water treatment for Bitters as follows:
AMS: 104ml / hl (reduce alkalinity to below 50ppm)
mash salts:
Calcium chloride: 17g / hl
Calcium Sulphate: 17g / hl

The alkalinity reduction was pretty much what I'd been doing before, but I just finished my first brew (English best bitter) using this water treatment. The grain bill was:
pale male: 88%
crystal malt: 6%
amber malt: 6%

The alkalinity of the liquor after adding AMS came out at 35ppm on my test kit, and the mash salts were accurately weighed and added to the dry grain. My pH meter (which I just calibrated) showed the mash at 5.1 to 5.2 and even my cheap pH papers showed it much closer to 5.0 than 5.5

So I'm wondering if anyone has any suggestions or comments regarding the water treatment or why the mash pH was low, and should I try to raise it by altering the water treatment prior to the start of mash, or (as some websites seem to suggest) take a pH reading at the start of mash, and then add either calcium hydroxide or chalk to raise it then.

Any advice and suggestions gratefully received - as water chemistry gives me a headache!

[Eric]

A pH of 5.1/5.2 is what I would expect with 35 ppm alkalinity and that level of salts with that sort of grain mix.
I also wouldn't worry about that pH.

[JonA]

OK - but if you were wanting a "malty" tasting bitter, I've read here that folks are aiming for the top pH end i.e. nearer 5.5

I've never had much luck brewing those types of bitters - mine always seem to have a harsher taste than they should. If I wanted to get a mash nearer 5.5 than 5.1 for a more malty feel, any suggestions - less acid ? less calc. sulphate ?

I was wondering about the feasibility of doing mini-mashes with a couple of litres of water and tweak the water treatment. Problems with that are the quantites would become so small that any error would stuff the results completely - plus I don't really know what to tweak

[Blackjack]

Did you add the salts to the total calculated liquor. eg. I only have a small HLT and have to top it up and reheat for sparging while the mash is on.

Your water supply might/will vary considerably. and what might be analysed last month has changed when you brewed today

Beer and beer styles are remarkably tolerant and it is probably best to make salt and acid adjustments less rather than more and be at the top of the range for alkalinity rather than trying to aim for the absolute minimum "correct" figure.

Just a couple of ideas.

[Eric]

OK - but if you were wanting a "malty" tasting bitter, I've read here that folks are aiming for the top pH end i.e. nearer 5.5

I've never had much luck brewing those types of bitters - mine always seem to have a harsher taste than they should. If I wanted to get a mash nearer 5.5 than 5.1 for a more malty feel, any suggestions - less acid ? less calc. sulphate ?

I was wondering about the feasibility of doing mini-mashes with a couple of litres of water and tweak the water treatment. Problems with that are the quantites would become so small that any error would stuff the results completely - plus I don't really know what to tweak

Indeed some are aiming for pH values in that region. I don't subscribe to that philosophy, but not saying it won't work.
For a malty bitter beer with your water I'd reduce alkalinity to 20ppm, mash at 67C, get rid of the amber malt (possibly use Munich or Vienna instead), reduce the crystal, drop the gypsum, half the calcium chloride, boost the hops by 10% and not use Nottingham yeast.
Have you done an all pale malt brew? It's amazing how malty they can be, especially if you use a yeast such as WLP002, but then you'd wonder where the hops had gone.

[Eric]

Your pH is being pulled down by the amber and crystal as the residual alkalinity is but 35ppm. It is further reduced by the added calcium salts. By altering these accordingly you can increase the pH to your target. However, I've found that high levels of sulphates can make darker malt such as amber produce astringency in the finished beer.
Your water should be capable of producing good beers with little more than getting the alkalinity matched to your recipe, although sodium is higher than I'd like. An all pale malt grist using CRS to get alkalinity of all water down to 20ppm and using only the calcium sulphate, in the quantity advised by Murphys, should make a cracking beer.

[orlando]

Take a look at this graphic it illustrates quite neatly what we as brewers are aiming for in the mash and shows the desirable mash pH range and the temp range that favours alpha and beta amylase. In the text that follows the following point is made "Its notable from the graphic that the various enzymes work well across a range of pH. Therefore, targeting an exact mash pH is not critical to success. Achieving a mash pH that is within a tenth or two of the desired range can produce acceptable results. ".

The table following does take precision to the nth degree but I would be happy with the range you achieved. Eric's comments around the recipe are more relevant.

[JonA]

Yes I like that graphic - it clarifies things a lot.

Eric, thanks for your comments and suggestions. I knew about acid malts lowering pH, but I didn't realise that roasted malts have a similar effect. I've brewed with black and chocolate malts before so they would have really dragged down the pH.

I don't normally use amber, it was a clone recipe so I was just following the ingredients list. Next brew I'll do an all-pale recipe with the numbers you suggest. I must admit water chemistry is fascinating and I admire the folks who understand it. Maybe I should have listened more in chemistry at school!

[orlando]

Yes I like that graphic - it clarifies things a lot.

Eric, thanks for your comments and suggestions. I knew about acid malts lowering pH, but I didn't realise that roasted malts have a similar effect. I've brewed with black and chocolate malts before so they would have really dragged down the pH.

I don't normally use amber, it was a clone recipe so I was just following the ingredients list. Next brew I'll do an all-pale recipe with the numbers you suggest. I must admit water chemistry is fascinating and I admire the folks who understand it. Maybe I should have listened more in chemistry at school!

Another idea for you. If you don't like the idea of using acids etc, you could steep the dark grains instead. As they have no diastatic power it is not necessary for them to be in the mash. Steeping is also claimed to smooth out the roastyness of the grains, particularly if it is a cold steep. Interesting this brewing lark

[mark4newman]

Hi

What temp did you take the mash PH at. The 5.5pH is for a reading at room temp ie 21C

If you took the reading at mash temp, then it would need to be adjusted by about 0.35 (mash PH varies according to temp), so 5.5 at room temp is about 5.15 at mash temp, which is pretty much what you had.

Go on tell, me you took it at mash temp

[JonA]

That's something else I didn't know - I'll put steeping the dark malts on my list of things to try. Trouble is that to try out all these ideas you have to keep brewing and then drinking the stuff - oh well there are worse things in life


My pH meter has ATC but I did let the sample cool anyway and it got down to about 26c eventually, the reading had come up a bit from mash temp but by less than 0.1

[Befuddler]

If you can try to get your head round Bru 'n Water, it will calculate malt acidity for you and give a very good prediction of mash pH. You can then adjust your treatment to suit each recipe. It looks really daunting at first but you don't need a chemistry degree! You can figure it out just by reading the web page and playing with the sheet.

The main thing to be aware of is that the darker crystal malts contribute the most acidity, not the roasted ones as you might imagine. I think British amber malt would qualify as a crystal malt... I'm not entirely sure to be honest.

[JonA]

Thanks, I just had a quick look at it - as you say it looks pretty heavy stuff, but very interesting. Looks like there are a good set of instructions and it also calculates the acid contribution from dark malts. I see on the site it says that if you make a small donation to the project, you get an enhanced version which includes calculations for CRS (AMS), which would be useful.

[Dave S]

Thanks, I just had a quick look at it - as you say it looks pretty heavy stuff, but very interesting. Looks like there are a good set of instructions and it also calculates the acid contribution from dark malts. I see on the site it says that if you make a small donation to the project, you get an enhanced version which includes calculations for CRS (AMS), which would be useful.

Yes, there's no restrictions on how much you donate - whatever you want/can afford, and you get updates as and when too. Well worth it IMO.

[JonA]

I've just donated - working it all out should keep me quiet for w while