I use 50g each of citric acid and sodium bicarbonate which I simply weigh into a small bowl, then dump into 1 litre of cold water in a *large* beaker - it fizzes a lot. A few stirs later and it goes straight in the wash. This buffers the wash pH range to between 3 and 6.
I can't see any benefit in premixing for a couple of days - the chemistry is going to take place anyway, so my view is just make it when you need it.
For those interested, what actually happens is a molecule of citric acid reacts with 3 molecules of bicarb, producing 1 molecule of sodium citrate, 3 of water and 3 of carbon dioxide, hence the fizzing!
If you dry mix, you will get a slow reaction, and the stuff clumps together because of the water released.
Note - it's an endothermic reaction, meaning temperature of the mix will decrease, but in the quantities used, not enough to freeze your fingers!
Note also to be chemically correct, more citric acid is needed than bicarb, but I can't remember what the ratio is, and for our purposes I don't think it's relevant.Statistics: Posted by hampk — Mon Apr 03, 2017 1:08 pm
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