by db1979 » Tue Jun 11, 2019 6:55 am
6 kg of sugar is more than you want for a 21 L wash, try to stay at 1 kg sugar per 5 L water maximum. Otherwise the yeast gets stressed and start making off tastes that carry through into your product.
As far as heating water, use as many lots of 1 L of boiled water to dissolve your sugar and then dilute to about 18 or 19 L with cold water and check the temp, if it needs more heat, add more hot and continue until you're happy. The amount of water you'll need will depend on your cold water temperature.
I don't bother with using boiled water, I just blast it all with the garden hose (dissolves the sugar and aerates the wash and takes bugger all time) and then use an aquarium heater to keep the temp just right.