Tropical Fish Forum

Tropical Fish Keeping Help and Advice => Fish Tank Plant Advice => Topic started by: Andy The Minion on June 20, 2018, 11:11:28 PM

Title: Yeast CO2 optimum mixture
Post by: Andy The Minion on June 20, 2018, 11:11:28 PM
I'm aware that DIY yeast CO2 isn't the most popular topic in the forum, but just in case there is any I nterest I have an update on the Mk II yeastulator.
This system has been running for nine months now and I have been gently tweaking the yeast mixture to find the optimum that gives the longest sustained time between refills. This is a mix that gives more than enough CO2 and a good long maintenance interval.
Firstly, It is running on a 300litre tank which is normally said to be well above the upper limit for yeast systems because they 'cannot' generate sufficient CO2 or just take too much effort.
This mixture and the system in the link can easily achieve a stable day/night timed 30ppm CO2 level without adjustment for 6 to 7 weeks between yeast refreshes. I had found that a normal yeast setup on smaller tanks generally needs a partial change of the yeast every week and constant tweaking and this is why most people give up on yeast. Well don't, it much better than you think!

The quantities I have are for a 10litre yeast mixture (warning ! DON'T consider trying this quantity of mixture unless you use the storage/regulator system in the link)

The base is a brewing yeast, I have tried several brands and they all seem work equally well.
Feed stock is 2kg of normal white sugar, dissolve 500gm at a time in 1litre of boiling dechorinate water (1 drip of declorinator per litre)
Because I have very soft water I also add 1 spoon of bicarbonate of soda in each sugar mix. (4 level teaspoon in total)
Add 3 level teaspoons of yeast to a small quantity of warm water with a sprinkle of sugar to kick things off while you dissolve the sugar - don't add it to the sugar solution just yet.

The 10litre container will now have 4litres of very hot sweet water in it and would probably kill the yeast so add an equal quality of declorinated cold water to bring it back down to a pleasant 'babies bath' warm.
Then add the yeast mixture which should be starting to foam, and finally top up to 10litre leaving just a small air gap to prevent the mixture being forced into the tubes.
The mixture will be producing a good quantity of CO2 in an hour or so, but because the storage system is also a pressure regulator it should not require any adjustment, just check it the following day to confirm the header tank is filling up.
I have not found that the mixture needs shaking and I just ignore it only checking the header tank weekly to know when it starts to run out.

I have two yeast containers so while one is in use I leave the other filled with a water chlorine mix so it is clean for the next refil. This whole process takes less than half an hour, job done.

https://forums.thinkfish.co.uk/fish-tank-plant-advice/pressure-regulating-a-diy-co2-system/
Title: Re: Yeast CO2 optimum mixture
Post by: TopCookie on June 21, 2018, 12:15:56 AM
Interesting stuff Andy...  Does leave me curious as to what happens to the alcohol that must obviously be produced...?
Title: Re: Yeast CO2 optimum mixture
Post by: Andy The Minion on June 21, 2018, 04:47:34 AM
Well yes @TopCookie That went through my mind as well and I added 10 litres of cider to the system in addition to the yeast before Christmas as a trial. Well it worked and produced an acceptable scrumpy :)

BTW I didn't notice which folder I was in when a started and posted this in the wrong area, could one of the moderators move it please?

I tried to IM a mod but this function seems to be blocked, by "An error has occurred You are not allowed to access this section" Did somebody make me persona non grata?
Title: Re: Yeast CO2 optimum mixture
Post by: Matt on June 21, 2018, 05:03:03 AM
Moved  C:-)

I have noticed that pictures need to be saved as .jpg rather than .jpeg if that helps Andy?
Title: Re: Yeast CO2 optimum mixture
Post by: TopCookie on June 21, 2018, 09:26:15 AM
If it's of any help Andy, I use  https://imagez.to/  for posting pics online...  Really easy to use, to the point of being idiot proof really - a blessing for me, lolol...   ;D 

What I do is transfer photos from the phone to the pc, then open them up in "Paint" to re-size and/or trim them first, then it's a simple question of dragging & dropping the prepared photo into the upload box on Imagez and away you go...  Then you get links for posting on the web and simply copy & paste the provided url and use the "Insert Image" button on the forum... 
Title: Re: Yeast CO2 optimum mixture
Post by: TopCookie on June 21, 2018, 09:34:31 AM
Well yes @TopCookie That went through my mind as well and I added 10 litres of cider to the system in addition to the yeast before Christmas as a trial. Well it worked and produced an acceptable scrumpy :)

Point to note here:  yeast can only tolerate a certain amount of alcohol, and there's a cut off point at which the alcohol will kill the yeast - typically at around 17% abv or thereabouts (probably a lower figure in a more "uncontrolled" type environment - ie: one where an alcohol product is not specifically being aimed for)...  You should try the scrumpy thing again, but add apple juice instead of cider...  Another advantage of this would be that fruit contains fructose, which is a monosaccharide and really easy for yeast to work on...  This should help with the CO2 production too...  :)
Title: Re: Yeast CO2 optimum mixture
Post by: Andy The Minion on June 21, 2018, 09:46:19 AM
@TopCookie I reread the post and see I wasn’t clear before...of course I used apple juice, I was MAKING cider and added it to the system for the CO2 byproduct :) Hic  :cheers:
Title: Re: Yeast CO2 optimum mixture
Post by: TopCookie on June 21, 2018, 09:52:35 AM
I used to be heavily involved in the home brew scene many moons ago...  Was fantastic fun too...  I would compete with wines and beers, and did ok at it too...  Had to stop in the end though as it became too easy to have a pint of ale as soon as I'd get home from work each day and I started piling weight on as a result...!!!  So tempted to pick up the old hobby again now, but stick to wine this time...  Reading this thread has definitely set me off again...   :cheers:
Title: Re: Yeast CO2 optimum mixture
Post by: Andy The Minion on June 21, 2018, 09:54:15 AM
Thanks @Matt Afraid not it was a .jpg last time I tried. Perhaps it is linked to the blocked permissions- this was actually the message I got when I went looking for a moderator to request a message move and apologise for posting in the wrong area. I get the same if try to select any of the mods from your bio details in a previous post.
Thanks for moving it :)
Title: Re: Yeast CO2 optimum mixture
Post by: Matt on June 21, 2018, 10:20:34 PM
It might be worth contacting Robert directly to help resolve this.