did you use potassium sorbate to stop the fermentation? if not, it'll continue to ferment, if there is any sugar left. it'll never sweeten up on it's own. what you're tasting is normal for fermented cider, with no back-sweetening. what you need to do is, while still in the fermenter, add some potassium sorbate to stop the fermentation, then some more apple juice and maybe some brown sugar for sweetness, then after a couple days, bottle
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