The Planted Tank Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
I was making some bread and notice how strongly the activated yeast smelled when in the water/sugar. I am planning to use DIY co2 for my tank. Does it stink up the space?? Also, do you think I could head start the plants for a few weeks with co2 and then remove it when I get shrimp? Or does it need to be in longer to have a major effect. Thanks! Sorry if it seems like a dumb question!!!!!
 

·
Registered
Joined
·
2,450 Posts
Nope, it only smells when you open it up.
 

·
Super Moderator
Joined
·
11,986 Posts
As already mentioned by several people, the DIY CO2 solution will only smell when you open it up to replace the solution.

As for your second part of your question, it may take several weeks for plants to show a marked improvement after the addition of CO2. If you then remove it upon addition of the shrimps, the plants may fare worse. Fluctuating CO2 levels can promote algal bursts as well.

If you want to have a steady CO2 rate while keeping shrimp, then pressurized CO2 would be your best option.
 

·
Registered
Joined
·
1,458 Posts
Smells

1) The smell is an acetic acid(vinegar) and alcohol mixture reaction byproduct from yeast consumption of sugar.

2) Depends on how large your tank is, light setup, alkanity, pH, nutrients(fish waste/ferts), plant selection and tank temp. Anthing less than 20g, try two bottles of DIY CO2.

Larger tank?, you're going to want pressurized CO2 (once again this will depend on your plant selection and other parameters noted above).
 

·
Super Moderator
Joined
·
11,986 Posts
1) The smell is an acetic acid(vinegar) and alcohol mixture reaction byproduct from yeast consumption of sugar.
Fermentation by yeast does not produce acetic acid...
 

·
Registered
Joined
·
1,458 Posts
Fermentation by yeast does not produce acetic acid...
I interpret the smell to be due to (aceto)bacteria and not just yeast but I've read the following from a commonly searched article on yeast fermentation.

Acetic Acid(Vinegar)​
Acetic acid is the principle volatile acid in wine. It is produced during bacterial spoilage but is ALWAYS formed by yeasts
during fermentation. Beyond a certain limit, which varies depending on the wine, acetic acid has a detrimental organoleptic
effect on wine quality. In healthy grape must with a moderate sugar concentration (less than 220 g/L,​
Sacch. cerevisiae

produces relatively small quantities (100-300 mg/L).
The biochemical pathway for the formation of acetic acid in wine yeasts has not been clearly identified. The hydrolysis of
acetyl CoA will produce acetic acid as will aldehyde dehydrogenase by the oxidation of ethanal. Figure 6 shows the​
pathways used by yeast to form acetic acid


 

·
Registered
Joined
·
1,458 Posts
I also note that dead yeast collect as the sludge in the bottom of container, which could provide another nutrient source for bacteria in DIY bottle. So CO2/acetic acid/ethanol could be coming from other sources besides yeast.
 

·
Super Moderator
Joined
·
11,986 Posts
I interpret the smell to be due to (aceto)bacteria and not just yeast but I've read the following from a commonly searched article on yeast fermentation.

Acetic Acid(Vinegar)​
Acetic acid is the principle volatile acid in wine. It is produced during bacterial spoilage but is ALWAYS formed by yeasts
during fermentation. Beyond a certain limit, which varies depending on the wine, acetic acid has a detrimental organoleptic
effect on wine quality. In healthy grape must with a moderate sugar concentration (less than 220 g/L,​
Sacch. cerevisiae

produces relatively small quantities (100-300 mg/L).
The biochemical pathway for the formation of acetic acid in wine yeasts has not been clearly identified. The hydrolysis of
acetyl CoA will produce acetic acid as will aldehyde dehydrogenase by the oxidation of ethanal. Figure 6 shows the​
pathways used by yeast to form acetic acid


I also note that dead yeast collect as the sludge in the bottom of container, which could provide another nutrient source for bacteria in DIY bottle. So CO2/acetic acid/ethanol could be coming from other sources besides yeast.
Aha - then you are not talking about fermentation by the yeast -- some of the acetaldehyde that is produced can be oxidized to become acetic acid; however, this is not part of the fermentative pathway :) I think the sentence from your source that says that acetic acid is always produced during fermentation is slightly misleading.

Though contamination by bacteria is possible as well. All depends on your sterile technique.
 
1 - 12 of 12 Posts
Top