First time I've brewed anything and I thought i'd start as simple as possible, so I just got some granulated sugar and apple juice from concentrate. 2L of apple juice, Champagne yeast, and 2 cups of sugar (I couldn't find any recipes anywhere). I measured my starting density to be 1.21 (water being 1.00), and after 2 weeks fermenting at about 22C in a PET demijohn I have a density of 1.06.

I calculate this to give me an ABV of 19% roughly.

This seems to be too high to be accurate, so I wonder if anyone has any suggestions above and beyond just 'your hydrometer isn't working' as to what's happened? Does this sort of measurement sometimes indicate the cider is unsafe to drink or anything like that?

EDIT: All measurements were done at room temperature of 20-25C

  • Are you sure your starting gravity wasn't 1.021?
    – Denny Conn
    Commented Jul 30, 2013 at 16:24
  • Denny, if that was the case, how would it have a FG of 1.06? That would have to be a tremendous temperature adjustment miscalculation. What was the yeast that was used, and did you know the temperature of the liquid when you took your reading? Was the concentrate frozen liquid thawed and brought up to room temperature before measuring?
    – Scott
    Commented Jul 30, 2013 at 16:29
  • Edited post. Champagne yeast, and all measurements were done at 20-25C. Also yes I'm sure that my readings were that way around. The starting mixture was very thick with sugar, if I had put it into the fridge it would have probably made jam... and yet it wasn't too high for the yeast as it was bubbling away for 2 weeks pretty vigourously
    – user5866
    Commented Jul 30, 2013 at 16:37
  • 1
    I've heard of champagne yeast tolerating up to 18%, so this isn't out the realm of possibility. I'd say you're eyes and equipment aren't deceiving you here. What did you expect to come from a 1.21 OG?
    – Scott
    Commented Jul 30, 2013 at 16:44
  • I guess I didn't do enough research. Still, it takes ok so never mind! Thanks guys
    – user5866
    Commented Jul 30, 2013 at 16:51

1 Answer 1


2 cups of sugar weighs around 440g, so let's call that 1 pound. Sugar provides 46 points of gravity, per pound, per gallon. 1 pound of sugar in 2 litres (~ 0.5 gallon) would contribute 92 points of gravity.

Apple juice is typically around 1.060. Adding the 92 points from the sugar addition yields an estimated starting gravity of 1.152. To get the 1.21 original gravity reading, the apple juice would have had to have a gravity of 1.210 - 1.092 = 1.118 -- roughly double apple juice's usual sugar content. This is possible if you added less than the recommended amount of water when reconstituting the concentrated apple juice.

If you reconstituted the apple juice according to directions, I'd guess that your starting gravity reading was incorrect. This can happen if you don't adequately stir to distribute the sugar before taking a reading.

Either way, it's almost certainly safe to drink, aside from the usual dangers of high-alcohol beverages.

  • Nice. I did the calculations and got similar figures, but you beat me to the write up!
    – mdma
    Commented Jul 30, 2013 at 17:38

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