Oat Stout water calcs v low ph

[deeJay]

Hi Guys,
I brewed my first Oat Stout last week but couldn't get the PH up without putting my salt additions out too much but brewed anyway.
Got my target water was within recommended brewing range but PH for mash on calculator was 4.68.
To get it up to the 5.2 range I had to alter the salts so much that they no longer were in the normal range.

Question 1 - is there anything that will bring up PH without altering the target water too much?
Question 2 - my mash PH on the day was 4.9. will this affect the brew much or will be ok ?
cheers,

 

[Silver_Is_Money]

Flaked Oats are quite basic with respect to pH 5.4. Far more so than a barley base malt.
Pilsner base malt is often more basic with respect to pH 5.4 than other base malts.
Continental European base malts are potentially somewhat more basic with respect to pH 5.4 than North American base malts.

IMHO, there is no particular magic to be found via strict adherence to any so called 'water profile'. Baking Soda raises sodium, but running it to ballpark 50 mg/L (ppm) should not be an issue for Stouts. When it comes to raising mash pH, Baking Soda is your friend.

IMHO, I can't imagine any possibility of a mash ever going as low as pH 4.68. Even 4.8 pH is highly suspect.

pH 4.68 is 66% more acidic than pH 4.9. One must ponder where the extra acidity will come from.
10^-4.68/10^-4.9 = 1.6596

As to mashing at pH 4.9, it may pass more burnt harshness character from the deep roasted malts along to the finished Stout.

 

[deeJay]

Flaked Oats are quite basic with respect to pH 5.4. Far more so than a barley base malt.
Pilsner base malt is often more basic with respect to pH 5.4 than other base malts.
Continental European base malts are potentially somewhat more basic with respect to pH 5.4 than North American base malts.

IMHO, there is no particular magic to be found via strict adherence to any so called 'water profile'. Baking Soda raises sodium, but running it to ballpark 50 mg/L (ppm) should not be an issue for Stouts. When it comes to raising mash pH, Baking Soda is your friend.

IMHO, I can't imagine any possibility of a mash ever going as low as pH 4.68. Even 4.8 pH is highly suspect.

pH 4.68 is 66% more acidic than pH 4.9. One must ponder where the extra acidity will come from.
10^-4.68/10^-4.9 = 1.6596

As to mashing at pH 4.9, it may pass more burnt harshness character from the deep roasted malts along to the finished Stout.

 

[deeJay]

Hi, not sure what happened there, sent a blank reply.
Thanks for the reply, my grain bill is as follows.
25L into fermenter.
5kg ale malt
200g chocolate malt
100g roast barley
250g dark crystal
300g rolled oats
Home water: Ca=8.4 mg/l , Mg=1 Mg/l, Na=3.5 mg/l, Cl=3.7 mg/l, SO=2.6 mg/l
Target water is Brewers friend profile, Dublin dry stout (only stout I could find)

My salt additions to get water to recommended brewing range going off the calculator are, Epsom 5g, Calc chloride 2g, Chalk 18g.
once entered on the calculator the ph shows 4.62 ??

my understanding is that the roasted/crystal malts are acidic and so bring the ph down.
I am just going off what the calculator is telling me and to get the ph up to the 5.2 mark it says I have to add about 20grams baking soda?
How much is too much baking soda?
Maybe im using the calculator wrong?
appreciate your feedback.

 

[Silver_Is_Money]

When you say "the calculator" do you mean the Brewer's Friend calculator?

What is your waters Alkalinity (as CaCO3) in mg/L, and how many Liters of it were used in the mash?

 

[Silver_Is_Money]

Via a bit of cation/anion mEq/L balancing, I'm going to initially guess your waters Alkalinity (as CaCO3) at ~24.5 mg/L, and I'm going to additionally guess your mash water volume at ~20L.

With these guesses applied I would speculate that your mash should have been in the 5.4 to 5.5 pH range, as your deep roasted and caramel/crystal additions are on the mild side, and 4.9 pH requires them to be well more on the robust side.

But then you mention that you added a whopping 18 grams of Chalk (Calcium Carbonate), and that massive load of negatively charged carbonate ions should have easily sent your mash pH well into the 6's. The only thing potentially precluding this outcome would be the rather high insolubility of Chalk.

I can't imagine you mashing at a meter measured 4.9 pH (at room temperature) with your listed grist plus 18 grams of added Chalk, let alone mashing at a software projected 4.63 or 4.68 pH.

 

[Donoroto]

When it comes to raising mash pH, Baking Soda is your friend.

I have used food-grade lye (sodium hydroxide) once. Can't say if it made any real difference.

A low mash pH is not the end of days. It'll most likely turn out just fine.

 

[Craigerrr]

I use a bit of baking soda to bring mash pH up into range for porters and stouts. Two caveats, one, I don't use the calculator here on Brewers Friend, two, I don't check pH I just trust the prediction made by the software that I use.

 

[Silver_Is_Money]

@deeJay, did you perhaps run the Brewers Friend mash pH calculator in the "SRM Color" mode, rather than in the "Malt Bill" mode?

Aside: In my opinion the SRM Color mode for the determination of mash pH should be removed from Brewers Friend. Among several reasons for this (I.E., my opinion), who among us can precisely assess the % of SRM Color that is derived exclusively from Roasted Malts? The entry made within this field radically alters the projected mash pH prediction, yet the means to determine what proper valuation should be placed within this hyper-critical to the desired outcome field is likely a mystery to most of us.

 

[deeJay]

Via a bit of cation/anion mEq/L balancing, I'm going to initially guess your waters Alkalinity (as CaCO3) at ~24.5 mg/L, and I'm going to additionally guess your mash water volume at ~20L.

With these guesses applied I would speculate that your mash should have been in the 5.4 to 5.5 pH range, as your deep roasted and caramel/crystal additions are on the mild side, and 4.9 pH requires them to be well more on the robust side.

But then you mention that you added a whopping 18 grams of Chalk (Calcium Carbonate), and that massive load of negatively charged carbonate ions should have easily sent your mash pH well into the 6's. The only thing potentially precluding this outcome would be the rather high insolubility of Chalk.

I can't imagine you mashing at a meter measured 4.9 pH (at room temperature) with your listed grist plus 18 grams of added Chalk, let alone mashing at a software projected 4.63 or 4.68 pH.

Hi SIM,
Yes I meant BF calculator,
my Alkalinity as CaCo3 is 18.5 g/m3,
The mash was 27L as I used the Brewzilla 65L (small batch)
I use the malt bill mode in the calculator.
The ph on the day was 4.9 but that was meter in the mash not room temperature as you mentioned, never heard of taking it at room temperature before ?

Forgot to mention that I didn't add the chalk as it seemed like way to much and it put my recommended brewing range way out of whack but that is what the calc told me to add to get it up to around 5.2 as it was saying with my ph as mentioned in my first post was 4.68 ?

I'm thinking that I will forget about the recommended brewing range water profile and just aim to get my water in the mid 5 range.
cheers.

 

[Silver_Is_Money]

A pH of 4.90 when measured at mash temperature would translate to 'ballpark' 5.15 pH if measured at room temperature. Software based mash pH assistant calculators are designed to 'ballpark' predict mash pH as measured at room temperature.

By using my own means of deriving a prediction of your mash pH (the method for which is detailed in one of my posts to this forum) I come up with 'ballpark' 5.25 pH if measured at mash temperature, and 'ballpark' 5.50 pH if measured at room temperature, when utilizing all of the water and grist information you have provided.

 

[Silver_Is_Money]

Perhaps you entered nominal EBC scaled malt colors into the BF software while it was presuming the Lovibond scale. That would falsely drive the mash pH prediction way down.

 

[Silver_Is_Money]

pH measured upon a sample cooled to room temperature (as opposed to mash temperature) is intended to prolong the life of the meter and meter probe.

If you calibrate your pH meter at room temperature and then measure at mash temperature this will induce some degree of reading error if the meter does not have ATC. ATC may (or not be) be of a broad enough temperature range to compensate here, but what it does not compensate for is the factual pH difference induced by temperature differences. A measured pH of 4.9 at 65 C. is the real/actual pH. A measured pH of 5.15 at 20-25 C. is also the real/actual pH. pH is inherently lower at higher temperatures, and a proper and reliable temperature compensating pH meter will deliver the real/actual pH that it is experiencing at the time of measurement. ATC will not change a reading of 4.9 pH into a reading of 5.15 pH for your convenience. Unfortunately, most people likely believe that it will.

 

[Silver_Is_Money]

Hearkening back to my post #9 above, for those who actually prefer to use the "SRM Color" mode in BF, I've come up with some quasi-empirical and quasi-mathematically derived nominal 'ballpark' guideline entries to be placed within the "% Roasted Color" field as follows:

0.25% deep roasted as % Wt. of grist ~= 20% of finished beer's SRM color from roasted
0.5% deep roasted as % Wt. of grist ~= 30% of finished beer's SRM color from roasted
1% deep roasted as % Wt. of grist ~= 50% of finished beer's SRM color from roasted
2% deep roasted as % Wt. of grist ~= 65% of finished beer's SRM color from roasted
3.5% deep roasted as % Wt. of grist ~= 75% of finished beer's SRM color from roasted
5% deep roasted as % Wt. of grist ~= 80% of finished beer's SRM color from roasted
7.5% deep roasted as % Wt. of grist ~= 84% of finished beer's SRM color from roasted
10% deep roasted as % Wt. of grist ~= 87% of finished beer's SRM color from roasted
15% deep roasted as % Wt. of grist ~= 90% of finished beer's SRM color from roasted
20% deep roasted as % Wt. of grist ~= 92% of finished beer's SRM color from roasted

As always, trust but verify, as YMMV. But all I can suggest is that if your entry into the "% Roasted Color" field is total garbage, the pH adjustment suggestion given to you by the software will also be total garbage.

 

[Silver_Is_Money]

There are several pH meter phenomenon that lead to false low pH readings. Among them: Did you ever notice that while you are gently stirring a pH probe in the Wort the pH reading noticeably goes down? This is generally referred to as "stirring error". To read a proper pH the probe must be gently stirred only very briefly and then left to sit undisturbed by stirring or movement until the pH reading stops rising and stabilizes. The "built in" stability indicators provided are almost useless in assisting with this task, as they inevitably trip a false stability indication way too early. 30 seconds left undisturbed is better.

If you insist upon stirring during your readings, the only means to alleviate stirring error is to calibrate while identically stirring.

Another way to get a false low mash pH reading is to sample too early in the mash. Sampling at the 30 minute mark or later alleviates this issue.

And of course, reading the pH at greater than room temperature and then presuming this to be the same as for room temperature will yield a false low reading (albeit that for this case it is not the reading that is false low, but rather the readers misunderstanding/perception of it that is false low).

Lastly, an insufficiently or inadequately or too infrequently stirred or uncirculated mash can lead to local samples that are not globally representative and that are false low.

 

[Silver_Is_Money]

And then there is humanity's age old nemesis: 'Confirmation Bias'

Oddly enough, if your software predicts generally low pH results for the mash, all it takes whereby to help confirm its validity is to apply any of the various means whereby to achieve a false low pH reading. Problem solved! Plus as an added bonus, different software that makes higher mash pH predictions can now be summarily dissed as false, defective, and to be avoided. And all it takes is a little good old confirmation bias coupled with blind faith in ones chosen software.

 

[dmtaylor]

1. pickling lime.
2. your beer will still ferment at low pH but might end up tasting like olives. Strange but true in my experience.

 

[dmtaylor]

A pH of 4.90 when measured at mash temperature would translate to 'ballpark' 5.15 pH if measured at room temperature. Software based mash pH assistant calculators are designed to 'ballpark' predict mash pH as measured at room temperature.

By using my own means of deriving a prediction of your mash pH (the method for which is detailed in one of my posts to this forum) I come up with 'ballpark' 5.25 pH if measured at mash temperature, and 'ballpark' 5.50 pH if measured at room temperature, when utilizing all of the water and grist information you have provided.

+1 Ditto.

Based on ALL of the information provided above.... it looks to me like your real mash pH would have been about 5.45 to 5.5 (as measured at room temperature), which is good, and means that whatever way you used to calculate mash pH of 4.68 was somehow messed up, AND that your reading of 4.9 was somehow messed up.

How, I don't know.

My advice? Try not caring about salt additions or mash pH for a while, and see if your beer still tastes good. Works for me.