Boiling and cooling priming sugar can be a pain. There are advantages to this, but how much does it benefit the beer?
A further analysis of why these steps are preformed might help derive a better processes. I think it is possible to retain all of the benefits of boiling and cooling priming sugar without adding any time to the processes.
The benefits are two fold. Boiling the water and priming sugar allows the sugar to dissolve more easily and kills any microorganisms that may have been introduced. Cooling it keeps the yeast from being killed by the boiling liquid, and also keeps off flavors from being added into the beer that would leached out by pouring boiling water into the plastic bucket. HDPE used for food grade plastic buckets is rated for temperatures up to 190°F.(1) Exceeding that temperature could leach unwanted flavors out of the plastic and into the beer.
Killing BacteriaMost bacteria can be killed by flash pasteurizing. (2)(3) Tap water contains very little bacteria to begin with because there is no nutrients. For bacteria to grow both nutrients and water are required. Dry sugar also contains very little bacteria because there is no water. Therefore the amount of bacteria that may need to be killed is small. Heating to 165°F or above for a minute or longer is sufficient for most brewers.
Not Killing YeastYeast will be killed nearly instantaneously if shocked with 165°F degree water, so the common thought is that the priming sugar needs to be cooled before adding it to the bottling bucket. While it is true that the yeast will be killed at 165°F, it's also true that the temperature drops very quickly as cold beer is added to the bucket. Yeast, like most bacteria, will thrive at 110°F. (However, It will produce off flavors if fermented for a period of time at that temperature which is why most ales are fermented at 65°F an bellow.) The beer will likely be about 65°F or cooler at the time of bottling. 1 half gallon of beer plus 1 quart of hot sugar water at 165°F will yield a combined temperature of 98°F.
The Processes1) Add your priming sugar and water to a microwavable container. I prefer a mason jar.
For the correct amount of water and sugar to use
so as not to change the ABV of the beer see this post:
3) Remove from the microwave, secure the lid and swirl to dissolve most of the sugar.
4) Remove the lid and place back in the microwave for another minute.
5) Repeat steps 3 and 4 until the sugar is dissolved, and the temperature is above 165°F
6) Start the siphon of beer into the bottling bucket.
7) Once there is aproximently half a gallon of beer in the bucket add the sugar solution being careful not to splash the liquids.