testing and adjusting pH in mead

[gx37987]

So this is my first time making mead, I've made many ciders before so I am familiar in brewing but this will be the first time checking and adjusting my pH levels.
So a little background I decided to make mead because I starting beekeeping this year so I can get my honey for free. I've looked up many recipes for mead and decided on a very simple plan, it called for 12 - 14 pounds of honey and 5 gallons of water. so I mixed my honey with about 1 1/2 gallons of hot water to help dissolve the honey pourded it into my fast fermenter and added the remaining water to reach the 6 gallon mark. I checked my opening SG and it was off my scale way more then 1.160, I rehydrate my yeast EC-1118 and added 1 tsp of some yeast nutrient and the next day my air lock was bubbling just like when I make cider so it was looking great, a couple of day passed and my airlock slowed down to barely 1 bubble per minet, so a added another 1 tsp of nutrient and it kicked off again, a couple days later and no activity. So I know that my opening SG was high which could be why I have a stalled ferment but also could it be because the acid level is either too high or too low. I have a pH meter to measure what the level is. Also I have Acidex to raise the pH level and malic acid to lower the pH level. As well I have sodium hydroxide to find out how many g/L.
Sorry for the long winded story my question is how do I go about using the Sodium hydroxide? and what should be my target pH level be?

 

[bernardsmith]

Hi gx37987. The thing about honey is that when it is fermenting there are no chemical buffers in the honey to stabilize the pH and the pH can drop below 3.0 - A pH of 3.2 or higher is what you want But if it is considerably higher that's not really a problem. Yeast don't care if the pH is higher. A high pH may encourage bacteria but a pH of between say, 4.5 and 3.2 is fine. A pH of 3 or lower will likely stall the fermentation.
One pound of honey, typically, when dissolved in water to make a gallon, will raise the SG of the water by 35 points. Your 14 lbs of honey if you dissolved this to make 6 gallons should have given you a reading of about 1.090 (14/6= 2.33 ; 2.33 * .035 = 1..086) and 1.086 has a potential ABV of about 10 or 11%. If you got a reading of 1.160 then either you added far more than 14 lbs of honey or the sample you took to measure was not well dissolved...
Now, come time to drink your mead you might be interested in the TA (or equivalent) . TA is the AMOUNT of acid in your mead. pH is the STRENGTH of the acid. You don't taste pH. You taste the TA. Technically, TA stands for titratable acid and you want your mead to either taste pleasantly alive or if it tastes meh or tastes too sharp then you want the TA to be around .6 or .65 . TA and pH are not the same things. You can have a lot of a weak acid or a little of a strong acid or a lot of a strong acid or a little of a weak acid.. TA measures the quantity of the acid.
I will let others explain how to use the sodium hydroxide (to measure TA) but you can use your pH meter rather than use color change to determine how much NaOH you need to use to neutralize the acids. Color changes at a pH of 8.2 - so if you know how much NaOH you have added to hit 8.2 you know what the TA is of your mead.. BUT , as I say, you only need to measure this if the taste is too sharp or too bland and you want to get some idea of how much acid or base to add. Either that or you are in the business of selling your mead and your customers expect consistency across each batch

 

[gx37987]

thank you for the info so if I get this right then the procedure is to calibrate my pH meter to 4.0 then calibrate it to 7.0 pH, take a 15ml sample of my mead place the pH meter in the mead and add sodium hydroxide in 1cc increments till it reaches 8.2 then carry out the calculation for g/L and that will tell me the amount of acid I have in my mead. and weather to raise or lower the pH level.

 

[RPh_Guy]

Uh, question: TA is expressed in terms of a specific acid. What acid is in mead?

After digging into this a bit further I have a better understanding of what bernardsmith means here.

I know you're just quoting popular wine-making references... But personally I would call TA the CONCENTRATION of a particular acid AND IT'S SALTS. This explains the reason why it's a better measure for what we taste... as well as the reason it helps calculate acid/base quantities needed to adjust pH.
pH is a direct measure of acidity, a combination of strength and concentration. It doesn't matter what the acid is nor does it express how much buffered weak acid there may be.

In my opinion this definition of TA is much less confusing for someone with a chemistry background.

Back on track....
Although he didn't say it directly I think bernard was trying to explain that there is not really a "target pH" for the final mead, but rather a target taste -- better measured with TA... Measurements and calculations are great, or you could just add small amounts of acid or base to some samples until you like the taste, and skip the math and measurements.

I actually do adjust my cider. I take a baseline pH and then just wing it by adding malic acid to taste, without bothering with TA. My final pH usually ends up about the same.

Hope I haven't added too much confusion.

 

[mabrungard]

If your water had significant alkalinity, that could easily buffer the pH drop that should occur with fermentation. Using very low alkalinity water like RO or distilled water should improve the pH drop. Its unlikely that your mead dropped its pH too far for the yeast to work...unless you added some other acid to the must. The ferment difficulty is more likely related to the high SG.

 

[bernardsmith]

I think you said it better than I did. Taste is everything and measurements are very little because the actual target is never going to be the same - the amount of alcohol, the real sweetness, the perceived sweetness, the tannin levels (tanninity?) all will shift where you WANT the acid level to be through taste. Wine ain't an engineered bridge. It's something organic and living. It's at least as much art as it is science and the science is backstage. The art is front and center. You could hit every target you aim for perfectly but the mead or wine can still be awful. The secret is not in being able to hit the targets but in determining what those "targets" should be for THIS batch.

 

[bernardsmith]

If your water had significant alkalinity, that could easily buffer the pH drop that should occur with fermentation. Using very low alkalinity water like RO or distilled water should improve the pH drop. Its unlikely that your mead dropped its pH too far for the yeast to work...unless you added some other acid to the must. The ferment difficulty is more likely related to the high SG.

But since honey has none of the nutrients or minerals that the yeast need using distilled water (I don't know what RO water contains) is dis-preferred in mead making. You want mineral rich water.

 

[growlrr]

RO = Reverse osmosis. I agree with Benardsmith. Unless you are commercially producing this to a standard, every batch will require some degree of "tweaking" to achieve what you want it to taste like. Sometimes it'll be very little work, other times lots of trial and error. I think a lot of the commercial meads are so bland in part because it is the easiest thing to reproduce consistently and without much messing around. My analogy would be akin to tuning a racing engine. You set every spec to where you think they should baseline, but I guarantee you you will test, adjust and tweak until you get "what works"...

 

[bernardsmith]

But isn't RO water mineral free? Is the pH 7.0? I don't know enough about how it is filtered... I only use water from NY State sealed springs for my mead making.

 

[stamasd]

Water, including RO, mineral and spring water, contains very little in terms of minerals with pH buffering capacity. We're talking a few parts per million. Check the analysis certificate. That in itself will do very little to control pH variations. It would be like adding a teaspoon of baking soda to a few hundred gallons of liquid that you want to change the pH of.

 

[bernardsmith]

Right... but the minerals have nothing to do with pH and everything to do with the needs of the yeast for cell wall repair and the transportation of sugars through cell walls. Where is the material for sterol production going to come from?

 

[Drewed]

I work in water purification. Ro and distilled are not the same thing. Water purity is measured by how much electricity it can (or cannot) conduct.
Pure water, 2 hydrogen-1 oxygen, will not conduct any electricity.
Tap water varies greatly depending on the source. From deep well water of over 1200uS to surface water around 200-400uS, to some sand point wells of under 100uS.
The more "junk" in the water ( minerals, etc ) the higher the conductivity.
Distilled water should be near 1
RO can be anywhere from 5 to over 100, depending on how clean the source is and "tight" the pore size on the RO is.

For mead there is not enough mineral content in most tap water to made a difference. You should be adding the correct nutrients to the must regardless of your source, and adding them before you pitch the yeast.