Do I have a PH Problem

[fields]

Hi Guys,

Thanks for the support given to me so far,

I've been going through the tried and true washes trying to work out which suits me best,

I've made 2 x 25L washes of Birdwatchers, DWWG, WPSOW and Rad's All Bran,

I have never had the explosive ferments mentioned that people have, and that does not concern me much,

I have been aerating each in the first 48hours by whisking with an electric whisk a few times each, have been using bakers yeast for all there has always been a sufficient turb at the bottom when each has finished, so I think the yeast is multiplying fine. Each wash when finished has ended up at 990. I've been using heating but with the infrared thermometer checked at various times of the day the temp ranges from 21C to 27C

What I have noticed with each is that on the third day of each the bubbling has really died down but the SG has not gone down much from starting, if I check the PH of my water its 7.1 using my digital ph meter and have calibrated it to bottled water which has 7.0... i'm getting readings on day 3 of 2.7 on average, after adding a lot of calcium carbonate to each back to 4.1ish on each they then go happily to completion.

The rads which is on at the moment started with a ph of 6 and then 3 days later was 2.6

WPSOW did it even with gypsum added which is supposed to act as a buffer,

What I'm trying to work out is my water dodgy or is this normal behavior if as I suspect its abnormal what can I add to my washes to buffer the PH to get more consistent conversion?

Cheers

[mash rookie]

You are over thinking this. Check your water. Unless your water is particularly acidic there should be no reason to adjust the PH on a new wash and never after the fermentation has started. You will not get an acurate reading.

Most ferments like to be slightly acidic and most recipes call for a little citric acid.

Typically calcium carbonate is only used with a sour mash ferment after several ferments.

If your washes are finishing dry (990) they are working just fine.

When the bubbling slows after 24- 72 hours it is transitioning from aerobic to anaerobic, (I usually screw this up and say it backwards) meaning it has consumed the oxygen, multiplied the yeast to saturation and is now starting to make alcohol.

Knock up a batch, leave it alone.

[fields]

Maybe I am over thinking it

Theres lots of discussion in WPSOW thread etc about having a ph under three giving off flavours and yeast performing best between ph 4 and 5

will there be less co2 when yeast are changing to anerobic? why does it feel almost stalled on day 3?

[Dnderhead]

if your wash went from 7 to 2.7 in 3 days something is wrong.
id check your meter .with a low ph solution

[mash rookie]

Maybe I am over thinking it

Theres lots of discussion in WPSOW thread etc about having a ph under three giving off flavours and yeast performing best between ph 4 and 5

will there be less co2 when yeast are changing to anerobic? why does it feel almost stalled on day 3?

It is not stalling if you are finishing at .990 When yeast is growing and consuming all available oxygen it gives off more co2 then when converting sugar to alcohol. You are fine. Quit looking at that damn PH meter. Set up your washes correctly, keep them at the correct temp and let them run their course. Have a couple of drinks and relax.
MR

[fields]

Ok, next time i'll do two side by side one ph adjusted and one not and see how we go... then i'll feel happy I can leave it alone,

As far as testing if its reading low ph (i use the ph meter for other projects as well) i was wondering what the best way to do that would be - would store bought vinegar have a known ph for example?

Thanks for your fast responses

[Dnderhead]

i'm not scientific enough to make buffer solution.that is what is used.
the meter needs to be cleaned and stored right or it wont read correctly.

[Bagasso]

I actually had a wash stall on me a few days ago. I have a ph meter and when I tested the wash it was below 3. I have never had a wash stall. What I did different this time was to use collected rain water. That had to be it because everything else was the same and my washes are always done in less than two weeks.

I adjusted the ph to 4.15 (not any particular reason just what the wash was at after a pitched in some lye) and now she is bubbling away again.

If you don't have your meter in a storing solution then the probe tip dries out. It would probably be a good idea to get a new probe and the buffer solutions to store and calibrate your meter.

[fields]

Thanks for the replies - I've been storing my meter according to the instructions (re read them the other day) but this does not mean that its not, not working

I don't actually drink that much but I think I'm enjoying this hobby for the experimentation and seeing the cause and effect of what I'm doing,

I'm considering doing 4 batches of the same recipe, one using tap water and being left alone, one tap with ph adjustment, one tank water left alone and one tank water with ph adjustment - then I can see when they finish and what makes the best difference

will post back when I do that... may be a month though

[gravy]

There’s lots of talk about pH and a good proportion of it isn’t quite correct.

You can find articles that talk about pH of 5.5 being optimal for yeast growth. Valid, but growth isn't the only important thing. A pH of less than pH 4.5 has better bacterial inhibition properties so is considered a better fermentation pH. A pH of less than 3 is generally considered to be stressful for yeast. That doesn’t mean that it will kill it, but in combination with other stressors it will definitely shorten yeast’s life expectancy.

When yeast utilizes nitrogen from ammonium it is converted back to ammonia and hydrogen ions are released back into the substrate. Since pH is essentially the measure of hydrogen ions this explains why pH drops during the yeast growth phase. If you increase the amount of sugar in your fermentations then you increase the osmotic stress at the start of the fermentation and ethanol stress at the end of the fermentation. For a successful fermentation you will need more yeast, but more yeast growth will also cause more pH stress.

And that isn’t the only problem… The absolute pH can cause yeast stress, but so does rapid changes in pH. I have had fermentations with a pH of 2.6 that I’ve adjusted back to 4.0 and it’s stopped the fermentation dead because yeast really don’t like rapid changes in their environment.

The reason this is a big problem for sugar washes is that they have no pH buffering. A pH buffer is defined as something you can add an acid or alkali to without an appreciable change in pH. A buffer is a combination of more than one compound. If your brew is too acidic then you can reduce the pH by adding potassium carbonate, but this is neutralization not buffering. It may reduce the stress caused by the low pH, but the change is relatively rapid and this in itself may cause problems, and so might a rapid increase in Potassium ions.

Since a lack of buffering is the problem I've had the best results from actually increasing the buffering capacity of my sugar washes.

Most people think of acid base reactions as a single direction process like adding vinegar to baking soda. Buffers work differently because they are a combination of an acid and its conjugate base. It’s complicated, but basically they are two-way acid base reactions. The most useful buffer from a fermentation point of view is the Citric Acid / Sodium Citrate buffer because is cheap and easy to make and it has a pH buffering range from 3.0 to 6.0.

Without buffering my brew pH would drop from 6.0 down to less than 2.5 in 24 hours. With buffering the pH starts at around 5.0 and finishes at around 4.0.

I make the buffer by adding 500g of Sodium Bicarbonate to 500g of Citric Acid (Anhydrous) and water. This is done before mixing up the brew – not in the brewing barrel. It fizzes a lot as the Sodium Bicarbonate is turned into Sodium Citrate. In these proportions the buffer produced has a pH of about 4.9. This quantity is enough for a 230 litre brew and is added at the start with the other ingredients.

If you do your atomic weights you will see this is more Sodium than is strictly recommended for a healthy fermentation, but not all of it is dissociated (available) and that’s important.

Using buffering (and other ingredients) I can ferment 300g/l sucrose to dry in 4 days.

[Bull Rider]

Thanks gravy, nice read...


Bull.