This entry was written at the end of August, and I apparently forgot to post it. It refers to tests performed 2013/08/28/
It looks like mixing order makes a difference with some ingredients.
During the period since it became generally accepted that baking soda/citric acid and/or baking powder are beneficial to bubble juice that makes use of Procter&Gamble detergents, there has been a lot of discussion as to whether mixing order makes a difference. For the most part, people have indicated that they had the best results when baking soda was added early and the citric acid added while all water was present. With baking powder, it has seemed that it was most effective when added when all the water was present.
While debugging eGoo, I mixed up 'fresh mix' batches which I diluted right away and noticed that if I used all of the baking soda+citric acid for the fizz mix that the juice did not work as well as if I used only a portion of the citric acid for the fizz mix and added the rest after adding the dilution water.
The differences for some are very subtle while for others the differences were great pronounced.
The answer seems to be the acidifying effect of the CO2 that dissolves in the water when baking soda and citric acid and water (or baking powder and water) react. Previously, people (including me) have focused their attention on the other by-products of these reactions rather than the CO2. However, it is looking more-and-more like it is the change to pH that is important rather than what causes it. And, since this seems to be of benefit even with distilled water....it is unlikely that it has to do with chelation (which helps the detergent deal with metallic ions in the water).
Recently, I have been exploring the Japanese Dishwashing Liquid, Charmy. Charmy's effective strength varies pretty radically in some pH ranges. When the pH of Charmy-containing bubble juice is adjusted to something in the 7.0-7.7 range, the detergent seems super-charged. (Note: I haven't tested enough to determine the precise range or what the behavior is like when the pH is below 7). With Charmy, the difference between a mix with and without baking powder (or baking soda+citric acid) is quite remarkable. (See the related blog posts).
A number of experiments with Charmy has led to the conclusion that it is the pH that is important for this super-charging -- as every method of lowering the pH to this target range was effective.
While Dawn and its relatives, do not respond to pH changes so obviously, I am beginning to think that the improvement that we see with baking soda, et. al. is due to pH adjustments.
With baking soda and citric acid at a 2:1 ratio, the result is mild acidifying of the solution caused by the carbon dioxide given off during the reaction rather than due to the solid by-products of the reaction. This made me realize that -- at least for me, whose water has a pH around 9 -- the mixing order is probably important. Since carbon dioxide quickly reaches saturation, if the CO2 is created before all the water is present, it will have little impact on the pH.
So, if one's water is alkaline, like mine, you need all the water present so that it captures enough CO2 to lower the pH of the mix.
I did a little test this morning to test my conjecture about the pH being influenced differently depending on when the reaction occurs.
Last night, I mixed up eGoo super-concentrate that had been prepared the 'classic' way with all the baking soda and citric acid used to fizz mix the PEO. I mixed up a gallon of the bubble juice.
I also mixed up two "fresh mix" versions. One version used all the baking soda and citric acid for the fizz mixing. The other version, used only 1/4 of the citric acid for the fizz mixing with the remaining amount added after the mix was complete and all water was present.
Dawn Pro pH measured at 8.3/8.4
Tap Water today: 9.7 (normally 8.9)
4.01 pH buffer solution: 4.1
NOTE The pH of our tap water was ridiculously high. It is normally 8.9-9.1, but the pH meter read 9.7. That is so high that I thought the pH meter might be broken. However, I tested a manufacture 4.01 buffer solution and Dawn Pro -- and the readings for both were correct. So, there is something weird going on with our water.
THE TEST MIXES
1) 'Fresh Goo'. Same ingredients as eGoo but mixed up and diluted in the same session. All bs/ca used for fizz-mixing.
2) 'Fresh Goo 2'. Same ingredients as 2 but only 1/4 of the citric acid was used for the fizz mix. The rest of the citric acid was added after all other ingredients (including all the water and detergent) were present.
- 1 - 8.7
- 2 - 7.5