DIY CO2 Trouble?

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black hills tj

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Apr 8, 2007
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Hey Everyone,

This evening I setup 1 2 litre bottle with 2 cups of sugar, some cool water, and 1/2 tbsp of yeast. I hooked it up to the power head intake and i'm not getting any bubbles. I do have a backflow preventer deal on the airline, but i've tried it on both ways and no difference. I did shake the bottle up a little to get things going. How long should it take before I actually get some CO2 production?

Thanks,

Mike
 
Thanks neilanh. If I shake it a little bit I can get a few bps for about 30 seconds, then it dies and sucks a little water a few inches back up the airline tubing. I'll give it some more time though. I only have 1 2-litre bottle right now, I plan on hooking up 2 more in 1 week intervals here though.
 
Thanks for the tip Rich. I only shook it when I did to speed the reaction up a little bit to make sure things were working at all. Hopefully it will get itself setup by the time I get off work this afternoon.

If all goes according to plan, I should start dosing on Sunday :)
 
Did you activate the yeast before putting it into the water/sugar solution?

When I was using DIY, I found it was best to activate first. Create your water/sugar solution in the bottle. Then, in a separate bowl, put a few ouncs of tepid (ideally 104°F water) with a bit of sugar, and add the yeast in. Stir gently to get a good mix, then cover it with saran wrap, and place a washrag over it (for darkness) and let it sit for 20 minutes or so. After 20 min, uncover it, and if you have tiny bubbles on the surface, you have good yeast that's been adequately activated. Try to have your bottles of solution around the same temp roughly, then add the activated solution to the 2L bottle mix.

I agree, shaking it really won't help and could cause a problem.
 
I used pretty cool water(wasn't sure what kind of heat would kill the yeast). I mixed the sugar and water, put it in the bottle. Then I mixed about 1/2 tbsp with some water and poured that in.
 
I think the cool water is the problem. :) I've always used warm water. Most of the time I put slightly hot water in with the sugar to dissolve it, then fill the bottle up to right below the neck with slightly cool water (together they make warm ;)) and then add the yeast. The yeast will be fine in warm/tepid water.
 
I did mine the same way as JustOneMore20. Hot water to dissolve the sugar than top it off with cool. Pretty much always started to produce in a couple of hours.

You may have old yeast, it's happened to me before. Mixed up everything like usual, no bubbles. If it dosn't start in 24 hours, get some new yeast and try again
If you are not getting any bubbles in your tank but you can see the bubbles rising in your 2litre bottle, your yeast is good, you have a leak in your system somewhere. Crank that cap tight. I have found leaks in my bottles by pinching the tubing shut, submerging the top of the bottle with tubing attached and give the bottle a squeeze under water. If you have a leak it will show up pretty quick. It only takes a small leak to stop the bubbles from getting to your tank.
Good luck :)
 
Well I don't go into that much detail. I use a funnel to dump 2 cups of sugar and 1/2 tsp of yeast into the coke bottle and turn on the water at the sink until it feels around 100 degrees by touch and then fill the bottle up to the point where it begins to taper. Then I cap it with a solid cap and shake the ever loving heck out of it and then uncap it and screw it into the injection system.

If I do both bottles at the same time I end up with roughly 48ppm CO2 a day later. If I do one bottle every Sunday alternating, then its usually in the perfect spot. I use a DIY CO2 reactor on the intake of my Rena XP2.

As you can see, other than measuring the sugar and yeast there is very little precision in making a batch. Of course when I first started I did it just like JustOneMore20 and Glenc where everything was measured and I used a thermometer to test the water temperature and I activated the yeast and dissolved the sugar before mixing the two... but as you get accustomed to doing it you find you can just play it by ear and it works just as well.

As for diagnosing your problem, I agree that cool water will not kick start the yeast. You can check for leaks too, make sure you have a good silicon seal around the bottle's entry point and that the seal on the inside of the bottle cap is not damaged (other than where you drilled it, if you drilled into the cap and not the bottle like I did) and then make sure it is tight.
 
Well, I warmed the bottle up with a heating pad(wrapped it around it and turned it on high) in an attempt to heat the water. I do get some gas production if i sit there and hold it tight around the bottle. I'm currently letting it sit there for a while to see if it will stay warm enough to produce some co2. This tank is in my basement and mom keeps the house around 70*
 
My CO2 mix works perfect for me everytime, it's simple.

I add 2 cups of regular sugar with a funnel into a 2 liter bottle.
Fill with water (slightly warm) to about 2/3rds.
Add 1 tsp of yeast from the little packet form the grocery store
add 1/2 tsp of baking soda

I do not shake the bottles ever, this will bubble 60 - 100 bubbles for me for up to 10 days then tapers off. I run 2 bottles like this changing 1 every 2 weeks. So each bottle lasts a month.

This may not be the most correct method, but it works flawlessy and easily for me.
 
Here's my exact method after a lot of trial and error (and recommendations by members on here):

-in a small clean glass add 1/4 cup warm water (~100-105F)
-place appropriate amount of yeast (1/4-1/2 tsp)
-add in a pinch of sugar
-mix well trying to get it to froth a bit, every minute or so I'll quickly beat the water like making scrambled eggs


-boil ~2 cups of water in a clean pot
-put the cap of your bottle in the water
-CAREFULLY pour the boiling water into the 2L bottle
-put the cap on and gently roll the bottle so the scalding water sterilizes all surfaces (please be extremely careful with the steam which will burn you on contact)
-add 1 1/4 cup common white sugar
-add a tablespoon of protein suppliment (I use old baby formula powder, a single container goes a LONGGGGGGGGGG way)
-mix for 20-30sec with gentle swirling (most of the sugar will dissolve because the water is so hot)
-fill 2L bottle with cold tap water to about 3/4 full while swirling
-the water temp in the bottle will now be about 100-110F which is perfect
-pour in the yeast mixture which has been sitting for about 10 minutes (and stirred every minute or so)
-gently swirl the 2L bottle so the yeast and sugar are evenly mixed together

Now (and this is very important), depending on the temperature of the room you may want to wait 30min or so before reconnecting the bottle to the tank. When hot things cool they contract. In your 2L bottle that means it will start to pull a vacuum (why the water gets sucked into the line). If you wait 30min or so the CO2 production from the yeast will pressurize the bottle against the vacuum and you won't get liquid sucked into the line.

Some final quick points:

-The time period with the yeast in the small cup is VITAL to the survival and production of the yeast. Do not skimp on this step. From start to finish it takes me a little more then 10 minutes.

-don't use baking soda (to buffer pH), the sodium in it is poisonous to the yeast, and yeast are well adapted to thriving in low pH conditions

-boiling of the water and then adding to the bottle will sterilize and kill most of the bacteria in the bottle. Bacteria will out-compete your yeast and cause a loss of production (or more likely a shorter production time, ie 10 days instead of 14). The boiling process will also remove most of the chlorine from the water, lowering the total chlorine amount when you add the yeast in.

-More then 1 cup of sugar (~10%) is toxic to the yeast. All you are really doing is wasting sugar, since yeast go dormant/die when alcohol levels go above 10% (for most common baker's yeast). If you are using more expensive wine/champagne yeast you can use more sugar.

-The protein powder (baby formula) is a trace nutrient supplier that will extend the life of the yeast and thus its production of CO2. Sugar provides the fuel source, but just like plants (and nitrogen), yeast require more than that to survive and thrive.

-You have a 29 gallon tank. I would recommend 2 2L bottles staggered a week apart (I do this with my 20 gallon setup). This will help to prevent BBA which is generally caused by fluctuating CO2 levels. By changing out a bottle each week (14days per bottle), you will have a much more consistent level of CO2. Another benefit is the virtual elimination of the vacuum effect in a 2-stage system since the new bottle is being pressurized by the old bottle. The CO2 might slow or stop from entering the tank but it should not back up into the tubing.

-Note that I use between 1/4 and 1/2 tsp of yeast (1/4 during summer months, and 1/2 during winter months). Many other recipes that call for more is because they are killing off a significant portion of the yeast due to improper practices (ie adding to cold water with no oxygen, baking soda, bacterial contamination, etc.)

HTH
 
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