PH buffers

[Myles]

Thanks for that.

My understanding was that 5 was a bit on the high side (for distilling) due to the issues with ammonia from surplus nitrogen.

I usually adjust it to 4.5 and test with pH 3.8 to 5.5 test strips from the home brew shop.
It typically ends up more acid but I have never had a fermentation fail because it got too acidic, so have never bothered with buffers before.

Is this use of buffers to maintain pH more of a flavour issue, than a fermentation issue? More important for beer?

[Mash]

I have had a few washes that produced a LOT of acid (due to poor nutrition is my guess) and the pH drifted down to about 4.5.

Chuck

he he

Pleased you said that - I have long suspected the same.

[Myles]

Just thought I would add this in for interest. It is actually taken from a Treatise to do with bread making, but is still of interest.

Yeast exhibits a considerable tolerance to extremes of pH, being able to maintain an active fermentation in a 5% glucose solution in the pH range of 2.4 to 7.4, but ceasing activity at pH 2.0 or pH 8.0. For optimum results, good practice dictates that the pH of the fermenting medium be maintained within the range of about 4.0 to 6. A drop of more than 50% in fermentative activity has been observed at pH 3.5. More gradual declines in yeast activity were encountered at higher pH levels, with measurable effects showing up at pH values over 6.0.

The explanation for the yeast's ability to maintain a relatively constant activity over a 100-fold change in hydrogen ion concentration (pH 4 to 6) is found in the fact that the pH of the cell interior of the yeast remains quite constant at about pH 5.8, regardless of any relatively wide pH variations in the fermenting medium. The enzymes involved in fermentation thus operate in an optimum pH environment within the yeast cell that is largely unaffected by external changes in pH.

[chill]

I started using buffers as the pH of my washes was dropping to 3.5 or below and resulting in a very, very slow ferment.

[Mash]

There has to be something to this. I aim for between 3.2 & 3.4 for red wine and quite frankly it goes like a train. 90% complete in 8-9 days.

In kale I have had no issue, indeed in anything I have no issue. The only reason for my test, was to see if there was a time gain to be had?

[chill]

That is why I use it - slow/stuck ferments, including the famous Lentil Wash. I am not surprised about the wine as there is loads of nutrition in that, the same for beer. Compared to wine and beer, what we ferment as washes is relatively nutrition poor and likely lacks the broad range of nutrients in a wine or beer. Turbo yeasts prove that this can be provided by careful selection of the nutrients.