My mash PH is low

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jonnyt

My mash PH is low

Post by jonnyt » Wed Feb 01, 2012 11:20 am

Guys,

I've done the Salifert test every time prior to brewing.
Using the calculator on this site I need 19ml CRS and 14ml Gypsum in 34 litres of water.

My last two brews have measured PH of 5.1 and 5.0 5 to 10 minutes into the mash.

Am I adding too much CRS and/or Gypsum?

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Eric
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Re: My mash PH is low

Post by Eric » Wed Feb 01, 2012 12:34 pm

Did you do a Salifert test after adding CRS? 19 ml is quite a small amount of CRS, twenty times that in the same amount of my water might get the mash pH down to 5.3, so those results do seem strange to me too. I wouldn't consider reducing the gypsum at this stage.
Can I suggest you do a staged test with CRS in your water and measure the results using your Salifert kit. It does seem queer.
Without patience, life becomes difficult and the sooner it's finished, the better.

jonnyt

Re: My mash PH is low

Post by jonnyt » Wed Feb 01, 2012 12:48 pm

I haven't done Salifert post treatment, but I've plugged my numbers back in the calculator and get the same results.
My Alkalinity is 130

boingy

Re: My mash PH is low

Post by boingy » Wed Feb 01, 2012 12:51 pm

Eric wrote: 19 ml is quite a small amount of CRS, twenty times that in the same amount of my water might get the mash pH down to 5.3
Blimey, Eric. Are you really using that amount of CRS? Doesn't that cost you a fortune?

My additions are similar to Jonny. I use 26ml for 50 litres.

Jonny, are you adding all of the gypsum to the mash? Typically a mash only contains about half the brewing water so you may want to put half the gypsum in the mash and the other half in the boil. I cant' say whether that will affect your pH - my grasp of water chemistry is not that great. What I would say is that I would be happy with a reading of 5.1.

jonnyt

Re: My mash PH is low

Post by jonnyt » Wed Feb 01, 2012 1:08 pm

I do BIAB so all water is in the mash.
Now that's got me thinking that the calculator is assuming a 2.5/3 to 1 mash ratio

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gregorach
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Re: My mash PH is low

Post by gregorach » Wed Feb 01, 2012 1:54 pm

jonnyt wrote:I do BIAB so all water is in the mash.
Now that's got me thinking that the calculator is assuming a 2.5/3 to 1 mash ratio
The water calculator doesn't make any assumptions about how you split your mash and sparge, it just works on a given volume of liquor.

How are you measuring your pH?
Cheers

Dunc

jonnyt

Re: My mash PH is low

Post by jonnyt » Wed Feb 01, 2012 2:10 pm

PH strips are used for measuring.

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gregorach
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Re: My mash PH is low

Post by gregorach » Wed Feb 01, 2012 2:37 pm

I'm not 100% convinced about the accuracy of the pH test strips I've compared against my meter...

What sort of efficiency are you getting? As long as it's reasonable, a point here or there off optimum mash pH isn't really a big deal.
Cheers

Dunc

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Re: My mash PH is low

Post by gregorach » Wed Feb 01, 2012 2:38 pm

Oh, and what sort of grain bills are we talking about? Darker malts reduce the mash pH more than pale.
Cheers

Dunc

jonnyt

Re: My mash PH is low

Post by jonnyt » Wed Feb 01, 2012 2:40 pm

Landlord clone so fairly light

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gregorach
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Re: My mash PH is low

Post by gregorach » Wed Feb 01, 2012 2:52 pm

Well, as long as you're getting reasonable efficiency, I wouldn't worry too much about it. Maybe try reducing the Gypsum to 10g and see how it goes.
Cheers

Dunc

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Eric
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Re: My mash PH is low

Post by Eric » Wed Feb 01, 2012 3:04 pm

boingy wrote:
Eric wrote: 19 ml is quite a small amount of CRS, twenty times that in the same amount of my water might get the mash pH down to 5.3
Blimey, Eric. Are you really using that amount of CRS? Doesn't that cost you a fortune?

My additions are similar to Jonny. I use 26ml for 50 litres.
No I don't. I treat the mash liquor with CRS then boil the sparge water in the hope that enough carbonate sediments or sticks to the side of the HLT. The water is so alkaline that I don't measure it until it's had a guestimated dose of CRS, then measure again after any further treatment. Mash pH was around 6 with untreated water and no amount of added gypsum ever shifted it. I could always brew a decent beer, just that it would never taste like what most people would expect.

EDIT: Getting my head into gear, I think 20 times is a fair bit out from reality, but I would use a lot of CRS were I to treat all my brewing water. This was why I initially queried if alkalinity was measured after treatment as I wouldn't need to use a much larger dose of CRS to eliminate any remaining HCO3.
Without patience, life becomes difficult and the sooner it's finished, the better.

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