its been 3 weeks now. bubbling hasn't stopped yet. there is very little sweetness.Best bet is to buy a <$10 hydrometer. In the absence of that, taste it and see if it still sweet. But, I also think three weeks from last bubble is also an indicator, but you run the risk of bacteria starting to grow in the wine.
thank you for your information. I really appreciate. I didn't get a hydrometer but after one little sip I can feel the effects of the wine. so I decided to rack it now before I run into a problem.Brix is the measurement of sugar in wine. Wine from grapes are typically start out 22-26 brix and you ferment it to zero, then backsweeten if desired. A white Zin will be around 1.5 brix residual sugar. A lot of wines from grapes that taste “fruity” will have .3 -.6 brix residual sugar. Your wine may have a low pH with the citric acid and could mask a lot of sugar. I’d certainly let it run its course, then after you do your first racking, leave an airlock on it, Incase it has some more to go.