I make a batch of Yellow Cat Sweet Cider every year and it always needs to be pasteurized. If you want sweet, carbonated cider in bottles without artificial sweeteners, it is pretty much your only option. While it can be a bit of a pain, this process is pretty simple.
In case you’re not sure what we’re talking about, I’ll explain the reasons for this chore. For this recipe specifically, I bottle cider while it is still fermenting. I want to maintain a low alcohol content and the natural sweetness of the cider but I also want the cider to carbonate. The continued fermentation carbonates the cider very quickly, but if it was allowed to continue past that point, the bottles would explode causing a serious safety issue and a huge mess AND a waste of some tasty cider. Pasteurizing uses heat to kill the yeast once it has completed the task you want it for and before it can create bottle bombs.
I also used this to stop the onslaught of infection in Hogun’s Mace Porter. Whatever wild yeast got into that beer carbonated it very quickly and probably would have dried it out to an extremely thin and sour mess. I was able to salvage it through pasteurization, though. Now, to get started.
You will need a pot. If you’re a homebrewer and not just a cider maker, your brew kettle will work fine. I usually use my canning pot because it has a wider base, allowing for more bottles. This time, I used that and a five gallon stainless steel pot I have to cut the time I needed to spend on the process.
Fill your pot or pots with enough water to submerge your bottles to the fill line. Remember that the bottles will displace quite a bit of water and the pot won’t need to be as full before hand as a result. With the water in place, it is time to bring in the stovetop portion of stovetop pasteurization.
Heat the water on the stove top to 180º. You can go slightly higher, but make sure you don’t hit 200º. If the water is too hot, it could cause heat shock and shatter the bottles when you stick them in. Once you’ve hit the target temperature, turn off the heat and REMOVE the pot from the burner. Even if it is turned off, the burner will still be hot and could shatter your bottles.
With your water at 180º and your pot off the stove, you can start adding the bottles to be pasteurized. Do not put too many in at a time. They shouldn’t be touching. Beyond that, you can use your judgement. When all the bottles are in, cover the pot and leave it alone for ten to fifteen minutes. I usually give larger bottles a bit more time. I did a couple quart bottles and a couple growlers this time and I decided to leave the growlers for last and just leave them in the pots overnight.
After that time, you can carefully remove the bottles. They will, of course, be hot. Use proper precautions. Sit them aside to cool off, still not touching. You can now start reheating the water for the next set of bottles. By the time that set is done, if you’re using twelve ounce bottles, the first set should be cool enough to be handled and put away, but be careful anyway. You can repeat this process as many times as necessary.
When you remove the bottles, they should be very cloudy. The yeast, if it was before, will no longer be settled at the bottom of the bottle. Everything will be mixed up, but don’t worry, it’ll settle back out and now your bottles will maintain the carbonation they had when pasteurized. You may still want to keep them separate from other bottles for a week or so just to be safe, but if the time and temperature were right, they should be fine.