Myth busters - the real truth on CO2 in indoor grows

for the record, co2 at 1250 ppm at 9 pm. i may need to scale up the ingredients a little if this falls below 1000 ppm tomorrow morning. oh well, tinker and tinker, we'll get it right.

homebrewer said:

The catch is that disaccharides (honey, or a maltose) is MUCH more expensive than simple table sugar.

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point.

you could also cut your pitching rate in half (use less yeast) to see if that helps extend your ferment.[/QUOTE] tried that in experiment 3, but the fermentation still seemed to peter out by the end of the third day. maybe it's alcohol intolerance and not sugar depletion that's stopping my reaction? some internet dimwit suggested tasting the mix to tell the difference, but i am not that committed to this experiment.

If your fermentation has stopped, then the sugar has fully fermented. Instead of tasting, a more accurate tool would be a hydrometer found at any local homebrew shop. They may run about $9 and will tell you how much sugar is in your solution at any given time.

How warm is your room? Dry yeast usually gets rehydrated at 104* before pitching into beer. So if your room is 80-90*, that is definitely not too warm for the yeast and they will work MUCH faster at those warmer temps. Also, my recipes were designed around a 10-14% alcohol tolerance so the when keeping the ratios the same, you should still be below the alcohol tolerance of the yeast.

homebrewer said:

If your fermentation has stopped, then the sugar has fully fermented.

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ok, I'll go with that. This formula has worked pretty well so I'm going to stick with it for this experiment but I ordered some safe-ale (sp?) yeast to try next.

Any ideas about how to recover yeast? Maybe if I let the containers sit for a day after use in the refrigerator?

Co2 at 1325 at 8 am, so the fermentation has been pretty consistent this experiment. I'm scaling up the ingredients to shoot for 1500 ppm. With a net gain of 600 ppm to get to 1250 i need another 40% to reach 1500, now I am adding 1.25 gAllons water/.75 pounds of sugar/21 grams yeast each day.



Edit: 1525 ppm at noon with increased ingredients.

Co2 at 1400 ppm just before adding new containers at 9 am.

well gang, i'm headed out of town for a week, so the experiment's shutting down too until i get back. i did work up some preliminary economics based solely on the size and characteristics of my grow room, so these numbers are not in any way universal although the relative economics between options shouldn't change all that much.

note that the fermentation daily costs look high, primarily because i am still adding quite a bit of yeast daily, something i should be able to cut down on going forward. if the yeast can be reused at an average rate of 90% (average 10 uses before discarding) then the economics of fermentation look pretty good. i'll verify the ability to reuse the cheap yeast when i get back. also note in all cases i did not include a co2 monitor/controller. part of the purpose of this experiment is to see if you can get good results without one.

....................................cost per day used...........cost of start up
co2 from fermentation*...... $1.64................................$27
co2 from tank**.................$0.70..............................$400
co2 from propane***.........$0.27..............................$455

* 61 cents per day is new yeast which should I should be able to reduce to close to zero by making more use of used yeast from previous days. Fixed costs include the ingredients for all containers and $20 for a two-time co2 test kit.

** co2 from a tank is used only on average 15 hours per day, so only a fraction of the co2 produced by fermentation is needed if you use a tank. Start up costs include tank, regulator and timer as well as a two time co2 test kit

*** estimated 15% of co2 is wasted via pilot light when the lights are off. Start up costs include generator, propane tank and two time co2 test kit

Thank You very much for doing this. You have done a freaking amazing job and you damn well could charge for information like this with all the work you put in.

ColaFarmer said:

Thank You very much for doing this. You have done a freaking amazing job and you damn well could charge for information like this with all the work you put in.

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You're welcome. But like most of the stuff I do I'm using it myself so it's just one extra step to record it here and this is a handy place to keep records anyway. Plus I get pretty direct feedback that helps a lot when I get lost.

True... I have just about all of your threads saved. You're the man. You don't skimp on your information and don't seem to miss much while doing it.

I have always heard the simplest way is the best. Maybe it would be more wise to just provide cheap circulation and be done with it.

another experiment would to maybe see how much co2 dry ice emits...
maybe this way u could have a sealed room without aircooled lights...

I think a good experiment would be to see if the elevated levels of CO2 actually increase your yields to the point where your time, effort and money are justified.

homebrewer said:

I think a good experiment would be to see if the elevated levels of CO2 actually increase your yields to the point where your time, effort and money are justified.

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good point

whne conditions are prime co2 benefits far outweigh the cost

View attachment 1034492View attachment 1034491i did have mine like that.2L bottle,1L of warm water,CUp of sugar,tblspoon of yeast,i didnt have the double air lock valve thing soo i just ran clear tube into that bowl of warm water.(which is now on a stand right up next to the base of the plants)since CO2 sinks and doesnt rise,putting it up higher is better.BUTT!!!! my tubing fell out of the bowl for a few hours i think and it stopped bubbling and had to start over and upgrade,soo do it carefully and precise.ITS A GREAT IDEA!!!AND SAVES MONEY!!

homebrewer said:

I think a good experiment would be to see if the elevated levels of CO2 actually increase your yields to the point where your time, effort and money are justified.

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Agreed it would be good but difficult to set up a good control. I'll work on it.

Back home and restarted co2 at 2pm using only used yeast. 1000 ppm at 5 pm.

So... how was your vacation???

ColaFarmer said:

So... how was your vacation???

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unfortunately sucked big time. But on the positive side came home to some phenomenally good looking plants cared for the first time by my nephew. Life evens out if you just give it time.

True story right there. Good to hear the hired help keep things in check, but i'm sure he was taught well. Can't wait to see the future experiments.

Toke on!!!