jescholler

Recipes 

Yesterday I did an all grain batch and measured my mash pH a little on the low side. I was using 4.6-6.2 strips from Precision Labs (Homebrew.com: pH Test Papers for Beer - 4.6-6.2) Here are the details:

Grain bill:
6.25 lbs Maris Otter (3L)
0.5 lbs Biscuit Malt (25L)
Predicted SRM: 6

Mash:
Thickness 1.3 qt/lb
Temperature 149F

Water:
90% distilled water, 10% tap water
Adjusted with salts per Palmer's spreadsheet to get the following:
Ca: 103ppm
Mg: 13ppm
Alkalinity as CaCO3: 59ppm
Na: 20ppm
Cl: 124ppm
Sulfate: 69ppm
RA as CaCO3: -23
SRM Range: 3 - 8

Here's my procedure:
-Added water to mash tun, about 10 degrees above strike temp.
-Added salts to the water and stirred (ended up stirring a lot to bring down the temperature more quickly).
-Added grain to the mash and stirred until all grain was fully wet.
-Placed lid on mash tun and stirred after about 10 minutes.
-Checked pH about 5 minutes later (measured just below 5.0).
-Stirred some more and checked again after 5 minutes. No change.
-Added 1/2 tsp. chalk, stirred and checked after 5 minutes. No change.

After 60 minutes, I did an iodine test and MAYBE had a very small amount of starch, so I went an additional 10 minutes. I ended up getting 76% efficiency.

Now I know the ColorpHast pH strips have been known to measure the pH about 0.3 low. In my case, that would put my mash pH at about 5.2. I'm tempted to think that my mash pH was on and I'm getting some inaccuracies in my measurements. Any thoughts?

__________________
Harsh Bitterness Experiment

Primary: Not until fall :(
Bottle: English Barleywine, Bird Dog Brown (ABA), Skull Splitter IV APA
On Deck:

boo boo

Recipes 

Did you check your pH at room temperture or at mash temperture? pH measurements should be made at room temperture.

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How do you BBQ an elephant....first you get your elephant....

jescholler

Recipes 

That's a pretty important detail isn't it? It was measured at 149F (mash temp). From Palmer's spreadsheet:

For best results, for all beer styles, the mash pH should be 5.1–5.5 when measured at mash temperature, and 5.4–5.8 when measured at room temperature. (At mash temperature the pH will measure about 0.3 lower due to greater dissociation of the hydrogen ions.)

So if my measurements were accurate, the pH was still a little low. I know Palmer's spreadsheet is just a ballpark estimation, but my RA was pretty close to that of Dortmund (-4 vs. -1). The Dortmund Export is supposed to be 4-6 SRM, and my beer was 6 SRM. I'm pretty sure the pH was good, I'm just curious as to why my strips didn't represent that.

__________________
Harsh Bitterness Experiment

Primary: Not until fall :(
Bottle: English Barleywine, Bird Dog Brown (ABA), Skull Splitter IV APA
On Deck:

MattHollingsworth

Recipes 

When I input these numbers into Palmer's Spreadsheet, I see an RA of -33 not -23.

For a color of 6 you'd wanna hit an average of -20 RA.

__________________
HOMEBREWING SINCE 1997

jescholler

Recipes 

I think that's because you have "bicarbonate" selected in cell E14 rather than "Alkalinity as CaCO3".

When I change cell E14 to bicarbonate I get an RA of -33 as well.

__________________
Harsh Bitterness Experiment

Primary: Not until fall :(
Bottle: English Barleywine, Bird Dog Brown (ABA), Skull Splitter IV APA
On Deck:

MattHollingsworth

Recipes 

Ah makes sense.

__________________
HOMEBREWING SINCE 1997

-TH-

Recipes 

If those strips do measure .3 low, AND you adjust for temp, doesn't that put you in range? ie: 4.9 +.3 +.3 = 5.5

__________________
TH

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jescholler

Recipes 

That's correct.

__________________
Harsh Bitterness Experiment

Primary: Not until fall :(
Bottle: English Barleywine, Bird Dog Brown (ABA), Skull Splitter IV APA
On Deck: