Low PH

[invisigoth]

Feel free to post your question :handgestures-thumbupleft:

kewl! i expect the question will get moved to the appropriate section but....
doing second gen of hooks rum. the recipe suggests that calcium carbonate isn't necessary till 3rd gen. it's been slowly ticking over for a couple of weeks with enough nutrients added. i did aerate. taped off a sample today and the ph was 4.6. was just trying see see if i could find any posts that hinted that low ph might retard yeast activity in general. :o

[Kimbo]

I dont know of any posts but the amount of dunder you use will affect the Ph.
maybe get some test strips and see what your Ph level is ;-)

[invisigoth]

I dont know of any posts but the amount of dunder you use will affect the Ph.
maybe get some test strips and see what your Ph level is ;-)

erm, like i said.... 4.6. i don't use test strips on coloured solutions, as the pads get stained by the solution so the colour change is not accurately comparable to the comparison chart. :geek:

the question however was "does low ph inhibit yeast activity?" :teasing-tease:

[Kimbo]

I believe it does ;-)

[Lupus]

I was under the impression that yeasts actually preferred more acidic conditions.

In all the reading I have done, I seem to remember somewhere that yeasts prefer a slightly acidic environment to grow in, and have traditionally been associated with the spoilage of acidic foods. As they ferment the sugars, the by product of their metabolism continues to acidify the environment, with little to no fermentation occurring under pH 4.2

Hence the need to neutralise the acidic environment with the continual reuse of dunder in subsequent washes.

[bt1]

Yeh 4.6 is a little low/ acidic. it's only marginally above the acid level of a pure tomato paste.

For a general yeast aim for 5.00 to 5.5

Some specialist yeasts prefer near neutral at around 6.0.

Above 6.0 as a startin point you risk alkaline washes along with bacteria, spirit discolouration and a variety of new alcohols, esters you don't want to meet.

In truth historically yeasts have been selectively developed to suit these pH ranges avoiding bacterial infections, especially from AG washes over the years.

If like self your intrested in yeast microbology let me know I'll post you a heap of journals/extracts etc for backgrounders OR in short just go to God's own site John Palmers Brewing site and get a 20 pager on yeasts, pH and nutrition.


bt1

[invisigoth]

thanx guys :handgestures-thumbupleft:

If like self your intrested in yeast microbology let me know I'll post you a heap of journals/extracts etc for backgrounders OR in short just go to God's own site John Palmers Brewing site and get a 20 pager on yeasts, pH and nutrition.

actually i am interested yeasts. a few years ago i missed the opportunity of microbiologist position at a place that was trying to develop a saccharomyces strain that could utilise cellulose to produce fuel alcohol. i haven't had a chance to read much of it yet, but i recently added "brewing yeasts and fermentation" to my book collection. looks to be pretty comprehensive because it deals with both the biochemistry of yeast metabolism as well as yeast genetics, both of which interest me. :geek:

in the past most of my musts/worts have been naturally acidic without being excessively so for me to think too much about it. i overlooked the metabolic acidification of the dunder added to the second gen, but come to think of it, meads can be notoriously slow to ferment even with sufficient nutrients. i'd always put that down to the natural anti microbial activity of pretty well much all honeys, but it could also be due to the high acidity of honey. :think:

i was using the still spirits rum distillery yeast.

[Rumdrinker]

I have had issues with rum wash with a low PH that required raising the PH & a yeast bomb to get going again.
4.6 should be fine though, mine got down to ~3.5 when it stuck which is way to low for the yeast.
Sounds like your on the right track though, monitor your PH with an electronic PH meter & keep the PH in check & you'll be able to keep your rum generations kicking along nicely.