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Old 08-12-2012, 08:41 PM   #1
snail
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Default First brewday measuring pH

I bought a pH meter after reading for weeks about water, minerals, acids, etc etc. I brewed a Pliny the Elder clone today and took some pics for a little feedback.

*****************Water Profile***********************
pH 7.7
TDS 122
Conductivity .2
Cations/Anions 1.8/1.7

Sodium 14
Potassium 2
Calcium 16
Magnesium 5
Total Hardness, CaCO3 61
Nitrate .3
Sulfate 4
Chloride 16
Carbonate <1
Bicarbonte 59
Total Alkalinity CaCO3 48


******************Water Mineral Additions**********************
Gypsum (CaSO4) 9.9mash/ 8.7sparge
Epsom Salt (MgSO4) 3.0mash/ 2.7sparge
Calcium Chloride (CaCl2) 1.5mash/ 1.3sparge
Lactic 88.00 % 0.0mash/ 1.1sparge

**************pH Summary*****************
pH @ 5mins: 5.76
pH @ 10mins: 5.72
*Added 1mL Lactic Acid
pH @ 20mins: 5.68
ph @ 30mins: 5.63
End pH: 5.39
End of sparge pH: 5.73
Boil pH: 5.45
End of boil pH: 5.06


Mash in pH @ 5mins


Mash pH @ 10 mins


Put 1mL of Lactic acid into mash
Mash pH @ 20 mins


Mash pH @ 30 mins


End mash pH


Now on the end of mash pH reading I took I used a turkey baster and took the sample from the middle of the mash. All the others were from the ball valve. I think this is why the last reading was so different. I'm not sure if the pH was ok or if after I added the lactic it was good.

Sparging, added 1.1mL lactic to sparge water


End of sparge pH, Gravity was 1.014


Preboil was 1.044, was supposed to be 1.054, added all the DME I had and was at 1.050. pH was at 5.45

End of boil pH, Gravity was 1.072


Finished racking to fermenter


If you look close there is an oil slick on the top. Never had that!


Ahhhhh, post brew day homebrew (Amber Ale)

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Old 08-13-2012, 12:06 PM   #2
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The first question I always ask is 'Was the meter calibrated using a procedure like the one laid out in the Calibration Sticky?"

Initial pH reading seem high as distilled water pH for most malts is around 5.76 and you have a lot of calcium. Of course your water could be high in alkalinity.

Meter samples should be drawn from the body of the mash after thorough stirring.

pH at the end is where you want it to be. Thus you have demonstrated that the proper amount of lactic acid for this grist and water is the 1 mL. Next time put that in at the beginning.

End of sparge pH is higher than the widely recommended limit of 6. Your water must be pretty alkaline.

End of boil pH looks good.

But don't stop taking readings there. An observed pH drop into the 4's a few hours after pitiching is a good indicator that fermentation is underway well before any physical signs are visible.

Your post would have been a lot easier to read if you just tabulated the results instead of posting pictures.

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Old 08-13-2012, 01:24 PM   #3
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Quote:
Originally Posted by ajdelange View Post
The first question I always ask is 'Was the meter calibrated using a procedure like the one laid out in the Calibration Sticky?"

Initial pH reading seem high as distilled water pH for most malts is around 5.76 and you have a lot of calcium. Of course your water could be high in alkalinity.

Meter samples should be drawn from the body of the mash after thorough stirring.

pH at the end is where you want it to be. Thus you have demonstrated that the proper amount of lactic acid for this grist and water is the 1 mL. Next time put that in at the beginning.

End of sparge pH is higher than the widely recommended limit of 6. Your water must be pretty alkaline.

End of boil pH looks good.

But don't stop taking readings there. An observed pH drop into the 4's a few hours after pitiching is a good indicator that fermentation is underway well before any physical signs are visible.

Your post would have been a lot easier to read if you just tabulated the results instead of posting pictures.
Thanks for the reply AJ. I edited the post and put my water profile and a summary of the pH readings like you suggested.
The meter was calibrated before mashing in and verified in the calibration solution.
I thought the initial mash pH was high too. I don't think my water is too alkaline. The water profile was sent to Ward Labs in 01/2010. My water may have changed but according to the water service records, the water always stays about the same. Some ions are a little higher or lower but nothing extreme.
Do you think the readings were off because I took the sample from the ball valve? My mash tun is a 15g Blichmann w/ false bottom. I'm thinking maybe the wort under the false bottom doesn't see as much of a pH change compared to taking a sample directly from the grains. That may be totally wrong...
I noticed you said the end of sparge pH was higher than the recommended 6. Mine was 5.73, I thought that was good?
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Old 08-13-2012, 01:56 PM   #4
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No, your water pH isn't that high at all. I would suspect that the readings may have been high because the lactic acid never made it beneath the false bottom or only did so partially. Recirculation of the liquid beneath the bottom should solve that problem but more importantly should get enzymes that have dissolved in that liquid back into the grain. Even so, taking the pH sample from the grain mass is a good idea.

Another thing to keep in mind is that there will be a learning curve with your pH meter unless you have used them before and are familiar with their quirks. It's not a steep curve and you should be taking measurements with confidence fairly quickly. Practice with fruit juice, coffee (cooled), milk, vinegar, lemon juice, sodas... is a good idea. Also, with the less expensive meters, it is a good idea to do the stability check in the Sticky.

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Old 08-13-2012, 02:29 PM   #5
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AJ was my end of sparge pH ok at 5.73? It's not higher than 6, the recommended limit.

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Old 08-14-2012, 03:30 PM   #6
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A brewer has two choices when it comes to mixing: move the media (the mash) or move the liquid (the wort). If there isn't much volume beneath the false bottom, then mixing the media could be effective in distributing ions throughout the mash. If there is some volume beneath the false bottom, then recirculation (vorlaufing) is the better way of distributing the ions. I use a RIMS, so the liquid is constantly circulated. The incomplete mixing might have been a source of the observed issue.

A pH of 5.73 is several tenths higher than desirable. A pH of 6 is an upper limit where tannin and other undesirable malt fractions are extracted at excessive rates. But even at 5.7, the level of undesirable fraction extraction is higher than at 5.4. Some refinement of the water adjustment and mashing processes might be needed.

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Old 08-14-2012, 04:18 PM   #7
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Wait, I have to get this straight!
So when everyone says, "Don't let the pH go above 6," when taking a pH reading you don't want the number to be 0-6, you want it to be somewhere 6>?

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Old 08-14-2012, 04:58 PM   #8
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Quote:
Originally Posted by snail View Post
AJ was my end of sparge pH ok at 5.73? It's not higher than 6, the recommended limit.
5.73 is fine. Overshooting sparge pH is one of those brewing bete noirs that people tend to get all upset over 'My sparge pH reached 6.01. Is my beer ruined?' There is no switch at 6.0 (or any other pH) beyond which all is lost and below which all is beer and skittles. Phenols are acids (straight phenol is also called carbolic acid) and they tend to dissolve more readily the higher the pH. Thus you will dissolve more phenols at pH 6 than at pH 5 but the pertinent question is 'how much more'. If the amount at 6 isn't enough to be problematic then the amount at 5.7 won't be either.

One of the reasons I say phenol extraction is overrated as a problem is because if it does occur the situation is easily repaired simply by lagering the beer for a period. Any beer improves as a result of some cold storage and one of the reasons for this is that phenols complex with proteins and settle out. If you are doing lager beer you are, of course, aware of this and do it as a matter of course. If you are doing ales primarily you might not be and, in particular, if you want an ale you can serve quickly you will want to be more cognizant of this potential problem that otherwise. Use 6 as a rule of thumb - don't consider it a hard and fast threshold that should never be violated.
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