Hey DTD,
There’s a few ways you can sweeten cider, from the simple to the complicated.
Firstly, are you going to keg this batch and put straight in the fridge or bottle and store at ambient temperatures?
If you’re going to keg and keep it cold, then a straightforward way is to keg/crash chill before kegging prior to fermentation is finished and leave some residual sugar there. You just taste and then crack on when happy with the result. You run the risk of leaving some byproducts of fermentation there though, which the yeast would usually clean up for you.
Lactose is another option, but I’ve always found it leaves a funny taste in my cider and I’ve never been a real fan (also not a fan of milk stout/beer which has lactose added either).
There’s a few artificial sweeteners people have used (stevia is one there’s been a thread on here), but I don’t know much about them. Again, likely to leave an artificial taste.
There’s various additives you can use to halt fermentation (potassium metabisulphate/sorbate), but I don’t have any experience with them.
Filtration is another option, although you need the gear and know how to do it. Same process as kegging prior to fermentation, you just filter instead of cool down when it reaches the desired level of sweetness.
Back-sweetening in the glass is probably the easiest and most reliable way. Just add a measure of juice to the glass and top off with cider (you may need to be a carbonate a little more to offset the juice you put in).
How you go about it will probably be dictated by your final packaging method and like all things brewing, it might need a little trial and error to get it right for your/your friends tastes.
JD
