Water chemistry help needed!

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jaytee22

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Hey guys, had an absolute nightmare brew over the weekend. Have brewed about 10 beers in my Brewzilla but decided to try one with the correct water profile and I think this started all my issues.

Bought a RO filter system and filtered my mash water. Tested the PH (with both a kegland ph meter and a cheap eBay one) and got around 6.8 - 7 which I've read is correct for RO water. My recipe stated I needed a ph of 5.2 so I then added 1ml of 88% lactic acid out of a total 5 that the recipe called for and the PH crashed to around 2.2 - 2.4.

I panicked a bit but upon further searching found that I needed to test it after I'd mashed in for 15 - 20 mins. So with that info I added the remaining 4ml of lactic acid and mashed in.

After 20 mins I found my PH had only raised marginally and was well below my 5.2 target (was about 2.8 - 3)

I pushed ahead with the brew but when I went to measure the gravity I was way off. Target of 1.074 and I got 1.045. I've never missed my targets by this much ever. I'm going to see this beer through just for experience sake but was very disappointing to be so far off with everything.

Does anyone have any idea what I'm doing wrong or what could have caused this? Am I meant to be diluting the lactic acid first? I just can't work out how such a small amount of lactic acid absolutely destroyed my PH.

Thanks in advance
 

MHB

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You need to measure the pH of the mash not the brewing water.
0.6ml of 88% lactic will lower the pH by 0.1pH/kg of grist. the grist (malt) has a strong buffering ability. Best to mash in, wait 10-15 minutes for everything to soluablise and stabilise (I do this at 20oC in a Braumeister), test the pH adjust to need.
If you want to mash in hot, its best to cool a sample to 20oC before measuring.
I would expect a Ro Water and grist with salts to be about 5.6-5.7 (for my water) adding your mineral salts (Calcium) will lower you pH, just use Acid to fine tune it.
If it was say 5.6 and you had used 6kg of malt and you wanted to go down to 5.2pH you need to move 4 points of pH. The amount of 88% Lactic would be 6kg grist*4 of 0.1ph*0.6mL = 14.4mL
Once the pH is right I ramp to my first rest temperature.
 

jaytee22

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Thanks for the reply, something is definitely going very wrong somewhere for me then because according to your calculations I'd need 14ml of lactic acid to drop it 0.4 yet with only 1ml of lactic acid it dropped over 3.0! I am definitely using 88% lactic acid so it seems I'm using the correct stuff.

If I'm after a mash pH of 5.2, what would you expect the water pH to be around when I just add my salts and acid?
 

MHB

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It’s really about buffering, if you are interested Braukaiser has a pretty good walkthrough that doesn't require a pHd.
If you look at a COA for base malt it will give a pH for the malt, that’s done in distilled water and a decent Pilsner malt like Weyermann comes in at 5.8. That’s measured in distilled water at about 8:1 water to malt.
Your salts (well the Ca in them) react with Phosphates in malt and will pull the pH down to around 5.5-5.6pH. Remember that there is a very finite amount of Phosphates so adding more salts won’t help you.

From there its adding acid to get the pH you want. 88% is a pretty common strength as is 100% and 80%.
Snip from Kunze
Acid.jpg

Mark
 

Grmblz

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If I'm after a mash pH of 5.2, what would you expect the water pH to be around when I just add my salts and acid?
Have another read of Marks ^ reply.
You can't get the water pH right before mashing in because the composition of the grist will affect the final pH, also by using RO water you are stripping all the minerals, and these will need to be added back according to style before mashing.
So, salts affect pH, and grist affects pH so these need to be added before checking/adjusting the final pH with acid.
Bugger ^ beat me to it.
 
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jaytee22

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Thanks for those answers guys, it's really appreciated.

Yeah I totally understand that final pH MUST be done after salts / acids and mashing it was just a warning sign for me on the weekend when my water pH was so low before mashing when I had only added my salts and acid. This was confirmed when even after the mash and wort cooled to 20c I was still way off so I thought there might be a ball park number I could aim for before mash in so I wouldn't waste all my grain like I did on the weekend.

After reading those articles that were posting it's telling me that something is going majorly wrong still as my lactic acid should not have affected the pH as dramatically as it did.

I think I will need to do some more testing before my next brew.
 

Skillz

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I definitely don't know much about the subject but my understanding is that the mash will naturally buffer itself to a close enough range for brewing.
That being the case I have to assume that your Ph meter is stuffed as it cannot be that far out.
I have only used a ph meter on my last half a dozen brews and it is always very close to what brewfather says.
Just for the record I use about 1.5 to 2.5ml of phosphoric acid at 96% to drop it usually from 5.5 to 5.2ish
 

MHB

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There is something in what Jaytee22 is saying. If you had pretty much blank slate (RoMo) water and added the amount of acid you said, the pH you have achieved is pretty much not possible. Which sort of leaves two possibilities, 1/ you haven’t added what you think or 2/ you aren’t measuring what you added properly.

The yield being ~40% less than expected (assuming your hydrometer isn’t out to hell) argues for your being well out of range in some of your additions.

Couple of things to look at: -
First up is to calibrate everything; do a two point calibration (7 and 4) on the pH meter; check your hydrometer and any thermometers you have; look at how you are measuring the acid and salts are they all accurate; check scales are the malt masses right... check everything
Just a note, biggest cause of wild results I have encountered is thermometers being way off, I think every brewer should have a decent quality laboratory thermometer they use to calibrate all other temperature measuring devices. I mean a decent one; have seen cheap thermometers that were 20oC out.

Is the reverse osmosis unit new? is it working properly (pH of water says yes - but check it) are you using it properly, the right amount bypassing, has it got one of those fancy Acid/Alkaline water modifiers?

This sort of thing can be very frustrating and when you find the answer its usually something pretty obvious (after you spot it) just go through everything systematically.
Mark
 

duncbrewer

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Another thing to remember is that the pH meter does need using properly unless you give that electrode a chance to get back to neutral ie waved around in some of your RO water you can transfer errors. It takes a surprising amount of water " washing " to get my cheap pH meter to settle.
After calibrating and using and washing you should store the electrode in a special solution between uses, not water not testing solution. This was a recent discovery for me and magically a pH meter I'd had for ages but didn't use ( my only one ) because it was rubbish now works great.
Also do check the concentration of your acid, just reading on US forum about mash not draining and no conversion, turned out that the OP had bought some new phosphoric acid which he used to lower pH. The supplier found out it was nearly 100% instead of the 10% on the bottle so all enzymes killed and just a large bag of porridge.
A little bit of acid goes a long way in water, but hardly anywhere in the mash.
 

jaytee22

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Thanks guys, they are all great suggestions. I will definitely do some further testing.

My RO system is a fairly cheap 3 stage system so I don't believe I'm starting with absolute perfect RO water but close enough for my level of brewing. It has only been used for 2 brews so far but maybe I'll go back to tap or regular filtered water for my brews while I sort it out.

I will test both my pH meters and possibly even verify my readings with pH test strips too. I didn't know about storing them in a special solution between uses so will look into that.

I will double check my lactic acid too, even though it says 88% on the bottle I just want to make sure. I agree that it should be impossible to crash the pH to such low readings with so little acid and think this is where my answer will be.

I use an inkbird electric thermometer so will test this also.
 

MHB

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I don’t think the Lactic will be the problem, even if it was 100% that’s only 12% stronger than the label says.
That isn’t enough to account for the observations made.
I know one of the major wholesalers sell 88% Lactic to lots of breweries and home brew shops so I suspect we are all pretty much using the same supplier and they are very reliable.
Care and feeding of pH meters is really important, they can turn into random number generators really easily, as a rule the cheaper they are the easier this happens.
Mark
 

Half-baked

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Just remember that while pH could be a factor, there could be lots of causes for low efficiency.
For example, for a standard batch size, an og of 1.074 would need a fair bit of grain. With bigger grain bill efficiency falls… not as much as you were expecting but might have contributed.
Can you give us some more info about the batch?
 

duncbrewer

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@jaytee22
I think half baked is on the right track. Assuming you have a brewzilla 35 to get 1.074 you'd need about 7 kg of 2 row malt and then to get 75% efficiency. That's asking a lot from such a big grain bill.
What volumes did you have for mash, sparge, boil and into fermenter?
If you used a lot of hops that also absorbs / loses you volume.
When I had a robobrew for really high gravity I could only really do half batches or reiterated mashes. The efficiency is very much a bell curve with grain mass across the bottom and extraction on the vertical axis.
I used and do still with the Guten 70 aim for just over 3 litres in the mash. 7 x 3 is 21 litres plus displacement by the grain is pretty full for the mash.
Lose about 7 litres in the grain means you can only sparge with 14 - 18 litres. That would be a very full 32 litres at the start of the boil , possible but exciting and then a long boil to get down to 22 litres prior to transfer and so some further loss to get 20 in the fermenter.

With either 7kg of ale malt or 7 kg pilsner brewers friend suggests 7.5 or 8 ml of lactic acid respectively for a total of 35 litres of water, all acid added to mash.

So I think this points to a pH meter error at measuring and the confounding problems of a big grain bill +- the other usual suspects in poor efficiency such as salts, grain crush, mash temperature too high, poor mixing and poor extraction on sparge. Lack of time can also be a factor .

Will await some numbers. To clarify my huge suppositions.
 

Grmblz

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+1 ^ I'm hanging out for the next episode, it's better than the murder mysteries on the goggle box.
 

duncbrewer

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@Grmblz
Read this thread for a good mystery.

 

scomet

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Try using this, It works for me every time for me with RO, didn't need to buy a $500 Ph meter but good to know its correct....
 

GregTheBrewer

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Jay, couldn't agree with Scomet more. I have been using Bru'n water for all grain almost since I started doing all grain. It really takes the guess work out of it, and makes mineral adjustment a breeze. It is a fabulous spreadsheet program, and though you can get it for free, fling Martin a few bucks for the effort he went to...that way you will get upgrades whenever he does them
 

duncbrewer

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Maybe @scomet and @GregTheBrewer could help out @mynameisrodney on this thread



I don't use Bru'n water so can't help.
 

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