Stuck. A healthy sugar wash ferments essentially dry, to 1.000 or below, because there are no unfermentable dextrins in plain sucrose. Stopping at 1.020 means roughly a quarter of the sugar is still sitting there unfermented.
The likely cause at 1.090: combined osmotic and alcohol stress on underfed yeast. At 1.020 the wash is already near 9% ABV, and if the nutrients went in as a single dose at pitch, the nitrogen ran out just as the alcohol stress peaked.
The restart sequence that usually works: confirm temperature is in the yeast’s range, add a small nutrient dose, rouse gently to resuspend the yeast without splashing air in, and give it 48 hours. If nothing moves, pitch a rehydrated tolerant strain such as EC-1118, which is the standard restart yeast precisely because it finishes hostile ferments.
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