[tommyboy22481]

This article serves as a beginner's guide to hobbyists looking to get started with DIY CO2, or making the switch to the Jell-O recipe.

The DIY Yeast method works on a simple principle, similar to wine-making (except we won't be drinking the brew). Yeast are single-celled microorganisms that ferment sugar for energy. The by-products are CO2 gas and alcohol. So, our aim is to get some yeast, give it some sugar and somehow "harvest" the CO2 gas and get it dissolved into the water so that it is available to the plants.

The traditional method has been in use for a long time in planted tanks. If consists of an airtight bottle containing water, sugar and yeast, airline tubing leading into the tank, and a means to get the gas dissolved in the water. While this method serves its purpose, it tends to start off with a burst of high CO2, then quicky tapers off and has to be replaced within 2 weeks. The quest for a steady and long-lasting method has lead to the development of the so-called DIY Jell-O CO2. In this recipe, the sugar is dissolved in the Jell-O, and the yeast is added on top of the Jell-O. It results in a more steady and longer-lasting CO2 production because the yeast only gains access to the sugar gradually, as the Jell-O is broken down. This recipe lasts me about 3 months, although individual results vary.

What you'll need:

• 2-liter bottle (soda or Gatorade bottles work fine) with cap
• airline tubing
• some kind of sealant
• drill, or a creative way to drill a hole
• water
• 1.5-2 cups sugar
• ordinary grocery-store baker's yeast, 1/2 tsp (Like Fleishmann's active dry yeast)
• 2 6oz packs of Jell-O ( or four 3oz packages )

Preparing the bottle
You will need to get one end of the airline tube through the cap into the bottle. Only an inch or so of the tube should be inside the bottle. Then you have to seal off any space around the opening in the cap using any airtight sealant that will stick. I'm not much of a handy-man, so you're on your own for this. I had a more mechanically-inclined relative do this bit for me. I think he used bathtub sealant and it has held for almost a year now. Some people have had problems with the cap not screwing in tightly enough to be airtight - my Coke bottle was fine. In fact, I have changed bottles and used the same cap on both without leakage problems. So be a little creative, or beg someone for help.

Now let's make Jell-O!

1. Mix together 2 packs of Jell-O (any flavour - all that's gonna go into your tank is the CO2 either way) and 2 cups boiling water. Mix really well until it's all dissolved.
   
   
   
2. Add 1.5-2 cups sugar and mix well again.
   
3. Add 2 cups cold water and mix AGAIN. Make sure the sugar is dissolved and not just collected at the bottom.
   
   
   
4. Pour the mixture into the bottle and stick it in the fridge overnight, until it actually turns to Jell-O.
   
   
   It should look like this in the morning.
   
5. Once the jello has hardened, add one cup room temp/lukewarm water and 1/2 tsp yeast. More yeast will produce more CO2. I would suggest starting with 1/2 tsp. If you find that it's not enough, you can always open the bottle later and put in some more.
   

I advise to starting with 1/2 tsp yeast, and work your way up from there. (You can also decrease surface agitation a bit to retain more CO2.) You should have a KH (carbonate hardness - if you don't have this test kit, you need it NOW) of at least 3 to avoid sudden pH drops (when carbon dioxide dissolves in water it acts as carbonic acid, lowering the pH and making the water more acidic). The greater the KH, the more your pH will resist changes.

Occasionally (once or twice) the yeast mixture on top will have to be refreshed with some more yeast and water. Just dump out about half the water and add some more water and yeast. I'm not positive but I think the alcohol level in the water gets to high and kills the yeast. You'll notice a slowdown of the mixture if you have a bubble counter and can adjust as necassary.

This guide was taken from here and modified.

 

[ninoboy]

Thanks for the info roud: The pictures answered all my questions. I;ve never made jello myself either :icon_roll

 

[cich]

Looks very professional too. Good work, and thanks!

--cich

 

[Rolo]

I just did the EXACT same recipe tonight (even orange flavor), except I'm using a 2-liter pop bottle instead of a Gatorade. I'm kind of concerned if this is too small. Right now the mixture is filled to just below the part the bottle starts to narrow. After adding another cup of yeast water later, I'm wondering if there won't be enough space and foam going up the tubes.

Does the jello "re-liquefy" after taking it out, so I could possible pour it into a Gatorade?

I also notice a ring of foam at the top of the bottle. In fact, its very unnoticeable, but the lower half of the mixture is clearer then the upper half. Seems like mixture isn't so uniform. Did you notice this Tom?

 

[tommyboy22481]

I would recommend leaving it in the 2 liter, I'm pretty sure that the gatorade bottle is actually a little bit smaller than a 2 liter so you should be okay. Maybe use a little less water in the jello next time.

 

[Rolo]

I noticed you're not using the exact "Jello" brand. So there's one difference between our setups. Otherwise since our recipes are similar in every other respect, this should be a very interesting comparison, perhaps showing which jello brand works better. I believe you said your using Fleischman's active dry yeast? Let me know so I can grab the same kind, therefore keeping the only difference in Jello brand. BTW, I used 2 cups of sugar, I don't know if you maybe only did 1.5 cups.

 

[tommyboy22481]

I am using Fleischman's active dry yeast, and I used roughly 1.75 cups of sugar. I used actual Jello brand last time but this stuff was cheaper so I thought I'd give it a try.

 

[bigpow]

what's that little blue tube?

BTW, nice documentation

 

[tommyboy22481]

I have my blue bubble counter stuck to the top of the cap with some double stick tape and I use blue silicone tubing for my Co2 line. I should get some Co2 resistant stuff but I havn't gotten around to it.

 

[Rolo]

Today I added the cup of water and 1/2 teaspoon of yeast (Fleischman's active dry). Right now its going at a steady 16 bpm. So far so good, I'm surprised it really works!

 

[Rolo]

It's been 5 days that my setup has been running. Right now the output has fallen to 7bpm from 16bpm. Doesn't it seem too soon for a slowdown? What to do?

 

[tommyboy22481]

Yeah that does seem a little early to be slowing down. I just timed my batch and its going at 18bpm, I'm not sure what could be causing such a big difference. You do have a very small volume of water right now, so maybe dillute the mixture on top and see how it reacts. Once the jello gets used up the water will have to be replaced less and less. I only had to do this twice on my first bottle although I wasn't keeping very close eye on it, as long as it was making a bubble every 3-5 seconds I was happy.

How are you counting the bubbles, counting 10 of them and then multiplying by 6 or something similar, or counting bubbles for a whole minute? Just to be consistent we should probably use the same method. I counted bubbles for a whole minute using a stopwatch to get my 18bpm measurement. Though not huge, there is more of an error when you multiply a smaller count.

 

[pufferfreak]

I just made this thing, Its chilling in one of my fridges. Does this method create more CO2 in the first 2 weeks then when you do the sugar water and yeast method?

 

[Rolo]

Yeah that does seem a little early to be slowing down. I just timed my batch and its going at 18bpm, I'm not sure what could be causing such a big difference. You do have a very small volume of water right now, so maybe dillute the mixture on top and see how it reacts. Once the jello gets used up the water will have to be replaced less and less. I only had to do this twice on my first bottle although I wasn't keeping very close eye on it, as long as it was making a bubble every 3-5 seconds I was happy.

How are you counting the bubbles, counting 10 of them and then multiplying by 6 or something similar, or counting bubbles for a whole minute? Just to be consistent we should probably use the same method. I counted bubbles for a whole minute using a stopwatch to get my 18bpm measurement. Though not huge, there is more of an error when you multiply a smaller count.

Actually, the top layer of water has increased to about 3" in depth, from 1" originally. Is it supposed to become less and less? It's probably the alcohol thats slowing it down. As I was still turning the cap off the smell of alcohol was very strong. I'll just try diluting it with more luke warm water and see what that does.

I've been counting the bubbles the same way - stopwatch for 1 full minute.

 

[Rex Grigg]

I use this same method for my 10 gallon tank. But instead of Jello® I use Knox gelatin. Also I cool the gelatin in a pan and then cut it into chunks and place the chunks into the bottle. More surface area that way. I always use a juice bottle and not a soda bottle as soda bottles are much to liable to fall over.

 

[Rolo]

I diluted it and there was only about a 3 bpm increase, from 7 to 10.

I think I know the problem. Every DIY setup I've done slows down around 5 days so I must be doing a consistent error. Out of curiosity I measured the GH of my tap COLD, and it came out to 21. When luke warm, it comes out at 10. Since our heated water is softened this means a lot of sodium (~50ppm) is in the water I'm using for the setup. I think I remember reading that yeast are not tolerant of sodium. Except then people are adding about a teaspoon of baking soda which adds over 500 ppm. ?

I'll try to work with the current setup now. I'm going to replace the entire top layer of water with 2 cup of microwave-heated, 100% hard water and a 1/2 teaspoon of yeast. Hopefully it will work.

 

[tommyboy22481]

Pufferfreak - The amount of Co2 produced is probably about the same or less than the traditional method, but it will keep producing that amount for much longer.

Rex - What kind of bpm are you getting using your method, and how long does it normally last?

Rolo - The volume of water will increase like you have noticed. I meant the water will have to be Replaced less and less. I dont know about the sodium, and I havn't been dechlorinating the water either. Maybe try mixing a batch using distilled water just as a control. If it doesnt slow down then you know its the water.

 

[pufferfreak]

Thanks Tommyboy.

 

[Rex Grigg]

I get a steady 10-12 bpm for over 30 days with my setup. Also note that I'm using wine yeast and it's a lot more tolerant of alcohol than bread yeast.

 

[TheSmJ]

What if both wine yeast and baking soda was used? Would this further increase the lifetime of the mixture?