Myth busters - the real truth on CO2 in indoor grows

[desertrat]

Nice experiment! It's no question that fermentation produces CO2, my argument was; is it worth the time, effort and cost? Subbed for your results.

haven't even thought about economics now but as to trouble there are people who collect rain water for god's sake. It really is pretty easy to set up and you don't have to visit the hydro store. I even avoided buying the trap with a little drip hose, some glue and a medicine bottle, and used the bakers's yeast you can find at any grocery store. I'm not sure I would have bought the gas generator if I had done this experiment first. Do you know how many different propane suppliers I rotate through for the gas burner. You want to talk aboUt a pain?

 

[Murfy]

this is all very interesting-

thanks desertrat

 

[Bigbux]

hey can i ask a slightly related question because ive searched the forums for a while and cant find the answer? i remember reading or hearing a while ago that co2 should b stopped prior to harvest. how long b4 harvest is best to stop co2 and why?

 

[desertrat]

hey can i ask a slightly related question because ive searched the forums for a while and cant find the answer? i remember reading or hearing a while ago that co2 should b stopped prior to harvest. how long b4 harvest is best to stop co2 and why?

. This may or may not make it to the list of myths. I've seen the same quoted in various chats/sites but have seen no proof at all. Kinda hard to test as it takes multiple harvests To prove.

 

[mydixiewrecked]

I use a 20 lb bottle I bought from a keg place, $109
I was given a reg.but about $120
I bought a sentinell c02 monitor, about $500
costs me $15 at the welding supply to fill the bottle every 3-4 weeks
so less then $800 for this whole set-up.
I also have a pretty well sealed room.
do you think this is to exspensive this way?

 

[desertrat]

It's too soon for me to be able to comment on economics. I'm still stabilizing the system, who knows what the final process will look like?

 

[desertrat]

So the experiments cratered I think because I didn't use hot enough water to start out. Heated the bottles up a bit and placed all of them in the veg room. Was 1475 ppm at 10 pm. That's 29 hours above 1000 ppm.

 

[desertrat]

experiment 2 and 3: 1550 ppm at 10:00 am, that's 41 hours above 1,000 ppm.

 

[desertrat]

1225 ppm at 7 pm, 50 hours above 1000 ppm. Looks like 2 1/2 days may be the limit. Any ideas on how to extend the time? Homebrewer or ninja??

 

[ColaFarmer]

So far I have to say, if you could get a dialed in rotation cycle of when to start the next bottle(s) [that way it is somewhat consistent CO2 levels during flowering] this would be very worth while...

Can't wait until you can give some expected costs, compared to tank/burner setup. Not trying to rush by any means, just the anticipation is starting to set in. LOL I think we'll all be surprised.

Great experiment! Like everything else you post, 110% effort and great information. Thank You!!!

 

[homebrewer]

The amount of CO2 produced is directly related to the amount of sugar used. I can't promise that you'll get a longer ferment, but I can promise that the amount of CO2 produced will be greater with a different recipe and hopefully those elevated levels aren't harmful to the plants. The funny thing about yeast is that regardless of the specific gravity of your mixture, yeast have a way of sticking to their own time frame as far as respiration, fermentation, and flocculation goes. So that means that whether you're using 30 lbs of sugar or 3 pounds, the yeast will ferment that out in 3-5 days (assuming enough yeast is pitched). However, there are a few factors that can dictate the speed of fermentation. Temperature, yeast strain, specific gravity, pitching rate and batch size will all play a role in the length of your fermentation so when manipulating these variables, you can manipulate your time frame.

The following recipe is scalable as long as you keep the ingredient's ratios the same:

1 gallon of water
2 pounds of sugar
3 grams of brewer's yeast

I'd suggest a 4-5 gallon batch size and recommend that you submerse your fermentation pail in a rubbermaid container filled with water. This will keep the fermentation cooler as yeast will work slower at lower temperatures. I'd also suggest swapping out frozen gallons of water every 12 hours in order to keep the temperature of the water cooler than the ambient air in your grow room. I don't know the alcohol tolerance of the yeast that you're using, but I'd suggest dry brewer's yeast for this next batch. A simple one to find is Safeale US-05 (or S-05). Between the higher gravity recipe, larger batch size, different yeast strain, and cooler fermentation temperatures, you should be able to lengthen the amount of time that your mixture is producing CO2, good luck!

 

[desertrat]

Still 1225 ppm at 9 am, that's 64 hours above 1000 ppm, or just over 2.5 days. Will keep going it stays below 1000 ppm.

 

[desertrat]

The amount of CO2 produced is directly related to the amount of sugar used. I can't promise that you'll get a longer ferment, but I can promise that the amount of CO2 produced will be greater with a different recipe and hopefully those elevated levels aren't harmful to the plants. The funny thing about yeast is that regardless of the specific gravity of your mixture, yeast have a way of sticking to their own time frame as far as respiration, fermentation, and flocculation goes. So that means that whether you're using 30 lbs of sugar or 3 pounds, the yeast will ferment that out in 3-5 days (assuming enough yeast is pitched). However, there are a few factors that can dictate the speed of fermentation. Temperature, yeast strain, specific gravity, pitching rate and batch size will all play a role in the length of your fermentation so when manipulating these variables, you can manipulate your time frame.

The following recipe is scalable as long as you keep the ingredient's ratios the same:

1 gallon of water
2 pounds of sugar
3 grams of brewer's yeast

I'd suggest a 4-5 gallon batch size and recommend that you submerse your fermentation pail in a rubbermaid container filled with water. This will keep the fermentation cooler as yeast will work slower at lower temperatures. I'd also suggest swapping out frozen gallons of water every 12 hours in order to keep the temperature of the water cooler than the ambient air in your grow room. I don't know the alcohol tolerance of the yeast that you're using, but I'd suggest dry brewer's yeast for this next batch. A simple one to find is Safeale US-05 (or S-05). Between the higher gravity recipe, larger batch size, different yeast strain, and cooler fermentation temperatures, you should be able to lengthen the amount of time that your mixture is producing CO2, good luck!

Thanks for the help, homebrewer. I'll try your suggestions out in a future experiment. Open question as to whether it's easier to replace fermentation bottles every two days or ice every 12 hours. I guess if I could get a week's run from a fermentation batch then it would be worth it. Also, in the d-I-y spirit I am trying to get baker's yeast to work. No question in my mind that you're right and brewers' yeast would work better, but who needs yet another specialty store you have to visit to be a good grower? You're probably a regular visitor to your brewery store so no hassle for you.

 

[homebrewer]

You're probably a regular visitor to your brewery store so no hassle for you.

That's true . But you only need to make one trip for two packs of yeast since you should be reusing your yeast batch-after-batch. Pro-brewers recycle their yeast for sometimes 10 generations until they see flavor issues. You're not concerned about flavor in this case though. Bakers yeast will ferment just fine as I've made decent (not great) mead with it, but it can behave a little different than brewer's yeast. Your call though.

 

[cymbaline]

I plan on making up some mead as soon as I find a local apiary to buy some honey off of.
In the meantime I took an old single burner propane stove and attached it to a tree off a 20# tank.
I fire it up on low when the day starts and shut it off around 30 minutes before bedtime.
No idea what my ppm are though.
I chuckled when you mentioned rotating through the propane distributors.. I know that feeling already myself hah
My conditions are not quite perfect yet but I swear I noticed some extra swelling within a day or two of adding some
more co2 to the room.. Maybe I'm convincing myself it's helping

 

[desertrat]

experiment 2 and 3: 1550 ppm at 10:00 am, that's 41 hours above 1,000 ppm.

 

[desertrat]

Experiment 2 and 3 petered out after 68 hours above 1,000 ppm. Now I'm going to see if I can sustain a sufficient and predictable amount of co2 over a longer period of time by rotating in new bottles as time passes. For experiment 4 I'm starting out with 1.8 gallons water/2.5 pounds sugar/10 grams yeast split into two containers, began at 2 pm today. Tomorrow I'm going to add a third container with half the volume of ingredients. Day after tomorrow and from then on I'm going to replace one older bottle with one new one. I'll end up with three bottles totaling 2.7 gallons water/3.75 pounds of sugar/15 grams of yeast in the room, one bottle new, one bottle one day old and one bottle two days old.

Edit: note that i increased the yeast to 45 grams as the lower amount did not support the level of co2 production needed.

 

[desertrat]

Experiment number 4 with co2 at 1025 ppm at 11 am before adding third fermentation container. Reused yeast for first time.

 

[moash]

Experiment number 4 with co2 at 1025 ppm at 11 am before adding third fermentation container. Reused yeast for first time.

how do u reuse the yeast?
by adding more sugar? or dumping the liquid out and using the sludge?

 

[desertrat]

how do u reuse the yeast?
by adding more sugar? or dumping the liquid out and using the sludge?

My first time trying it, but the sludge at the bottom is supposed to be full of active yeast cells, I dumped out 90% of the liquid and added new water and sugar.