Wiki member Susan(also known as Columbine the Butterfly) has suggested that Knox gelatin can be used to improve longevity in dry conditions -- even when it is hot and humidity drops below 30%. Like me, Susan reports that she has not found glycerine (which I have tried in ridiculously large amounts) to be useful for extending bubble lifetimes (at least of medium and large bubbles) in these conditions.
I mixed up some juice according to her recommendations though I have not had a chance to really test it. I will update this post when I get a chance to do a real test.
She recommends 4 packets of Knox gelatin per gallon of bubble juice. She instructs that the gelatin be dissolved in just boiled water and allowed to cool to 80F before incorporating with the other ingredients. She recommends that 1.5 cups (12 fluid ounces) of water (reserved from your bubble juice's total water needs) be used per packet of gelatin. She further instructs that the juice be allowed to sit overnight before use. Other brands of gelatin, Susan advises, are not effective. Susan's experience has been that trying to speed the cooling or mixing of the gelatin/water mix with the other ingredients prematurely can cause problems.
I made one half gallon of juice as follows:
- 1820 grams tap water put into a jug
- boil 3 cups of that water and remove from heat
- add 2 packets of Knox gelatin
- stir until the gelatin is fully dissolved
- put 1/2 tsp Bob's Red Mill guar gum powder in a salsa cup
- add enough 90% isopropyl alcohol to make a pourable slurry
- stir to make sure that guar gum is evenly distribute
- pour the slurry into the jug
- pour some water from the jug into the slurry cup, stir and pour back into jug
- turn the jug end-over-end a few times.
- wait until the gelatin mix is 80F
- pour the gelatin mix into the jug
- turn the jug end-over-end for a minute or so
- add 70 grams Dawn Pro to the jug and turn end-over-end a few times (gently so as not to create foam)
- add 1 teaspoon Rumsford baking powder and turn jug end-over-end a few times
I left the top off the jug open for about 10 minutes to let the excess carbon dioxide off-gas. I then closed the jug.
I did a brief test the next morning, and the juice worked well. My impression was that the film might be a bit thicker than without the gelatin, but since I didn't record the bubbles, I am not certain of this.
It was cool with 70% humidity. The bubbles did seem slightly longer lived than the guar juice that I tested it against -- but I did not have time to create enough bubbles to draw any conclusions. I am going to wait until a warm dry day to do a real comparison.
I will update this post when I do a real test.