One of the biggest time consumers I have on bottling day is cooling down the sugar to room temperature. So I have been thinking about sanitizing a small container the day before bottling, dissolve the sugar there, and seal the container. The solution should cool overnight and be ready to add to the bottling bucket the next day. Is this wise?
And on that note, I was thinking about doing the same for the gelatin I use to clear my beer, so once again, is this wise?
No need to cool it down. I don't. Beer turns out good anyway. Yeast doesn't die because it's such a small volume of hot liquid in a much larger volume of beer.
Nothing you propose to do is it bad, i.e you won't harm your beer by adding the hot sugar solution and or adding the Gelatine at the same time. So don't worry about that.
However; if your goal was to clarify the beer (adding gelatine) then the method you propose isn't efficient and you may undo the clarification process.
GELATINE
The best time to add the gelatin is right before you start the cold crash cycle, some people choose to cold crash it right down quickly others a stepped approach. Either way the gelatin is going to be most effective if added before the cooling cycle and allowed to sit for no less than a week.
PRIMING SUGAR
Adding a hot priming sugar solution won't harm the beer (not in small quantities) but, if added to a cold solution and or relatively cold given the temperature differences it will cause a new haze to form in the liquid, the same way mist does when the cold ocean air meets warm land. Yes it does go away - but I have found it returns when you eventually cool the beer for drinking.
If clarification wasn't a goal for you - I say go right ahead and just add everything onetime hot or cold - but because it appears to be (given the Gelatine use) you want to be a little gentler in inducing any shock to the solution. If you don't have temp controlled fermentation to be able to cold crash then allow priming solution to cool as you have done previously before adding.
Use a bain marie full of ice to cool your priming sugar syrup.
