CO2 in Root Beer

While searching the net for root beer ideas I came across a recipe that used food grade CO2 to carbonate root beer.

While the root beer was to be served freshly made, I was wondering if anyone had ever tried it and what your thoughts are on bottling it?

What is the issue you are raising... food as opposed to nonfood co2 gas or liquid? Or are you asking about dropping a dry ice pellet into a bottle, and capping fast?

I asked about food grade here long ago and got silence. Now I have learned to appreciate the character that soda picks up from dirty co2. Hopefully my paintball co2 bottle was machined out using used motor oil, and passed the savings on to me. The actual gas may have traces of banned insecticides for all I care... I gotta have my hourly hit of fizz!

Food grade co2? Hahaa
That stuff is really expensive.
I have a refill station with "food grade" co2 and will happily refill your non-food grade with my "food grade" for only $89.95 per 5 lb tank plus shipping...

I wasn't clear was I? The recipe called for putting food grade dry ice in the mix and serving it as soon as the dry ice had dissolved in the mix.

I expect you would lose most bubbles transferring the mix to bottles. If you add small pellets of known size to full bottles, it might be workable after some trial and disaster.

Trial and disaster would be a very accurate description. Carbonating with dry ice is wildly inefficient. The rate of sublimation (off-gassing) is much greater than the rate of dissolution (carbonating) into the liquid, so you waste a lot of CO2 to the air. A general rule of thumb for carbonating using dry ice is to use 1lb per gallon. You can normally get between 5 and 7 adequately carbonated 5-gal kegs of soda with a 5lb tank of CO2 by force carbonating in a keg. I'll let you do the math on that one.
Even with measuring out the correct weight of dry ice based on the volumes of CO2 that you want to carbonate to, putting that in a sealed bottle will likely build up too much pressure and explode before it can be fully dissolved.
We had a guy at our church do that with root beer at a Halloween party this year. He had a modified Sanke keg with a wide mouth threaded lid that he dumped root beer mix and dry ice into. The lid had some relief valves and about 10 seconds after he sealed it up, the relief valve opened and blasted the ceiling with root beer and covered the entire kitchen in a fine mist of root beer scented stickiness.
While carbonating with dry ice may be fun, there are better ways to add bubbles to your beverage.

Carbonating root beer with dry ice is a common picnic party activity. I've seen it done a lot. It's not nearly as efficient as other methods, but it's fun and easy.