# Two questions: acidity of mead and feeding yeast



## BernardSmith (Oct 23, 2012)

So last night I pitched a pack of Lavlin 71B-1122 yeast into 5 gallons of mead must (SG about 1.090 - potentially about 12% ABV) and after adding 2 T of acid blend the pH is 3.62. My question: Should I increase the acidity to around 3.3 by adding more acid blend during the first days in the primary or is it better to wait until all residual sugar has been converted to alcohol and then tweak the acidity? 
My second question is this: I understand that honey is very nutrient deficient for the yeast. I added DAP and energizer according to the instructions on the package but I have also read that it is important to feed the yeast after about three days of fermentation as they will have used up all the nutrients. Is it advisable to add the same amount of nutrient as I did before pitching the yeast or is that amount likely to create off flavors and the like? 
As always - thanks for any advice.


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## fatbloke (Oct 25, 2012)

A. Honey musts are generally acid enough. Anything added specifically to increase acid levels is usually discouraged, because the pH can swing wildly during ferment. Below 3.0 pH can cause stuck ferments, hence its generally considered best to add acid too taste after its finished.

B. Nutrients etc. The point of adding both, is to provide a broad spectrum of nutrient and an extra kick of nitrogen (as DAP/di-ammonium phosphate). With a staggered nutrient addition regime, you'd normally work out how much to use total, then split it into as many parts as you want. It seems that the best recommendation is to rehydrate the yeast with GoFerm (specialist rehydration nutrient), then once there's visible signs of fermentation, there is some research kicking around that states it as best too front load the nutrients etc to 85% of the total.

I'd guess that the pack instructions would be "total per gallon", so I reckon that if you used a quarter of that too help/supplement, it wouldn't leave enough for off flavours when its finished.

Oh, and don't use the "number of days" trick to work out when to rack. Let if finish first, then rack.....


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## JDC (Oct 25, 2012)

The ph of Honey is around 3.9 - when adding water to make must the PH will become more neutral. I have always had to add acid blend to adjust the ph before fermentation on my meads.


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## fatbloke (Oct 26, 2012)

JDC said:


> The ph of Honey is around 3.9 - when adding water to make must the PH will become more neutral. I have always had to add acid blend to adjust the ph before fermentation on my meads.


The pH of honey varies, its never a set point. I've measured my musts and have got from 3.3 to 4.8 pH. Plus while its up to the individual mead maker what technique they use, its been found that because of the swings in pH, like with wines, there's little point in using acid up front.

It's part of the reason for early stage aeration. Initially you add air/O2 for yeast development. But this has a side effect of creating the nucleation points that allow.the dissolved carbonic acid to connect and change to gaseous CO2 and emerge as bubbles - obviously this is quite a quick reaction, so it highlights a good reason to start a batch in a bucket, with plenty of headspace.

So that helps a bit with the pH swings early on, but the reaction is still developing other organic fruit-type acids (in a traditional its gluconic acids). Problem being that honey is a.very effective mask of acidity.

Hopefully my half arsed description sort of explains why you don't need to add acid up front, because you've already created the acid environment for the yeast by diluting the honey down to where it will ferment. Any addition will push it further possibly to the point where the yeast will stick. Fruits of particular types can do this "citrus fruits" being a good example.

Part of this controversy comes from archaic recipes, the lack of.understanding when they were produced and some of us trying to mimick them. Despite.them really have little.useful explanation as to how.things were actually done, historically. So.they really remain a list of.ingredients.

Nearly all current method and practice are.extrapolated from wine making, so its fine to.work the numbers, but its about the end product, so why do anything that could prevent you achieving a reasonable quality end product when you can modify it to best effect, rather than stressing the yeast before they've done their job........


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