pH Question

[Earendil]

Last night, I prepared a new must and pitched the yeast on it. While preparing the must, I checked the pH level and found that, with this honey (Pumpkin Blossom Honey, raw, purchased from a local beekeeper) the pH level was 3.52; I used a pH meter (pH Checker by Hanna) to measure it. I previously calibrated the device to be within 0.05 of the pH 4.0 and pH 7.0 solutions used to calibrate such devices.

I had read, in Ken Schramm's 'Compleat Meadmaker' that 'Morse and Steinkraus recommended a pH range of 3.7 to 4.6 for optimal yeast performance, and noted that 3.7 was high enough for yeast metabolism and low enough to retard undesirable bacteria.' Accordingly, I've been adjusting my musts to the 3.7 to 3.9 range.

I used Calcium Carbonate to adjust the pH balance and was surprised to find that 1/2 tsp was enough to adjust the balance from 3.52 to 3.8; I expected it to take more. I went ahead and prepared and pitched the yeast; it was fairly quiet and, even this morning, showed little activity.

In preparing my mead log for this 6-1/2 gallon must, I decided to check my Specific Gravity (1.114) and pH and was dismayed to find that the balance was at about pH: 3.55!! I immediately added more Calcium Carbonate, adding, shaking and then testing; another 1/2 tsp brought it close to 3.58; another teaspoon took it to 3.67 and another teaspoon took it to 3.8 or so.

You can bet that I went back several times, during the day, and re-tested the must to make sure that it was correct and consistent! It is now at pH: 3.81 and shows no signs of changing. How I blessed my luck and attention to detail in keeping my mead log!

I'm mystified as to how that initial addition of 1/2 tsp made such a difference. When I (luckily!) retested the must and realized how low its balance was, I thought that my pH tester might be lying to me. Any thoughts on this?

The Compleat Meadmaker also suggests that using Sodium Bicarbonate or other sodium-based alkalines can produce salty flavors, which sounds logical to me. Any other perspectives on this?

The must is now bubbling merrily, at about 18 hours from pitch.

Best Wishes to All!

 

[Medsen Fey]

Hello Earendil,

The reason that adding a liitle bicarb can raise the pH quite a bit is the same reason that meads often get pH drops - there isn't much buffering capacity in a mead must. Also the pH scale is logarithmic, meaning that a pH of 3.0 has 10X as much free acid (H+) as a solution with a pH of 4.0. As a result it takes a lot less bicarb to move from 3.5 to 3.8 than it does to move from 3.0 to 3.3.

Keep in mind that optimal fermentation pH is typically between 3.4-4.0. There is really no need to make adjusments for a pH of 3.5. I usually won't make adjustments unless the pH has dropped to 3.0 or below.

Medsen

 

[Earendil]

pH Perspective

Thanks, Medsen. I was going by what I had read; I'll heed your advice and make sure my musts are at pH: 3.5 or higher. I didn't know about the logarithmic nature of the pH scale; that explains the relatively large change in pH with that initial addition of Calcium Carbonate.

I'll post a meadlog for this must, which is looking excellent so far. I am so glad I've had access to the great advice on this site. I'm at the 1/3 sugar break, today, and will be adding a little nutrient.

Thanks Again!

 

[Oskaar]

Bear in mind that buffering your mead up to a pH of 4.0 or above will make you more susceptible to bacterial infections, especially acetobacter. I like to keep my stuff in the 3.3-3.7 range, sometimes lower depending on the mead and what I'm looking for in the flavor.

Acetobacter will also need O2 so just be sure to keep your carboys topped off with CO2 and monitor your pH.

Cheers,

Oskaar

 

[Dan McFeeley]

I'd like to add that usually, once you've gotten your starting pH to where it should be, you can simply leave it alone. I don't check the pH of a honeymust very often because I've found that so often it's right about 4.0. That's nothing to worry about. Once the fermentation kicks in, the yeasts will be secreting organic acids and gradually lowering the pH.

In other words, even though 4.0 is a little high, the yeasts will bring it down. It's sort of a survival technique -- yeasts can do well at lower pH environments than bacteria, so this allows them to dominate the food source.

So, to paraphrase, relax, don't worry, and enjoy your mead. ;D

 

[Matrix4b]

Along this line but not quite...

How does pH balance affect taste? I generally don't balance my meads and let nature take it's course. I haven't had a problem with any meads yet but I was wondering..Do people adjust the pH balance for taste reasons? Not just fermenting the Mead, of which I have no problems.

If so, what adjustments are better for what taste goals?

 

[Medsen Fey]

The lower the pH the more acidic tasting (tart) the mead will be. This acidity may be balanced by sugar, or alcohol, or other flavors so that even a mead with a very low pH may have a nice balance.

Once the fermentation is over, I do not adjust based on the pH number. I will make the necessary adjustments to improve the flavor, whether it means adding more acid or not, based solely on taste. Whatever the pH ends up being at that point, it is what it is. I will measure so that I know what the pH is as it has a bearing on how much sulfite I need, among other things.

Happy Mazing!
Medsen