SG of 0.900 after fermentation

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Jul 26, 2021
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This is my first attempt with a 4 week Cab Sav red wine kit.
After diluting the grape juice concentrate (Bentonite, oak chips) the SG was 1.090.
Added yeast, fermentation looked fine, lots of bubbles in the airlock, temp 65 to 75.
At day 14, SG is 0.990. I racked it today into a carboy
and added Pot-meta-bisulfafte and Kieselsol.
Also degassed with a drill + paddle for 5 minutes.
Then I tasted it: quite tart.

Do I have to be concerned ?
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Short answer... no need to be concerned. The experts will weigh in ... but that FG (Final Gravity), 0.900 looks extremely low (and nigh impossible). Use an ABV calculator with those numbers and you get about 25% alcohol and that is impossible with wine yeast supplied. Double check it... probably closer to 0.990... would be my guess putting you at a nice 13% alcohol... which would be on target. Many times beginners (as I did) will read a hydrometer wrong... or look at it backwards.
And young wine is not great but the good news is, it will get better, a lot better! Good luck!
Welcome to the forum :)

It is too early to be concerned. Kits are designed to give acceptable wine fairly fast. Also red wines are easier to make than whites and fruits. Having gas in a wine will make it taste tart, it will probably lose more CO2 by bottle time and taste better. If still tart sugar with a little potassium sorbate will do wonders.
Thanks for the encouragement, and yes, it is 0.990 (not 0.900).
I had followed the SG during fermentation:
Day 1: 1.090
Day 5: 1.030
Day 8: 1.002
Day 10: 0.992
Day 14: 0.990

Should I do the degassing step one more time ?
As it's been said many times on this forum... "Time is your friend." It will degas and clear over time... my experience, is that after having tried to "rush" some wines along, to meet the manufacturers 8 week time frame, I've ended up with sediment in the bottles... it is easier to let it sit, settle the fines, degas on it's own, and you get a nice clear, degassed, sediment free wine in the bottle. The guidance that I have gotten on this forum, for racking for clearing and degassing, once primary is complete is ... 3 days, 3 weeks and 3 months.... seems to be working for me. I can remember 3's.... I usually add it to the wine log so I know when it is time to rack again.

btw, your SG profile looks very good. You will be very impressed in a few months and more so in a year or two. I was a maker and drinker, until I figured out that you really need to make more wine than you drink (or give away) so that it will have time to age. My suggestion is to try Danger Dave's Recipe or Skeeter Pee for some quicker drinkers and let the grape wines sit... I'm no expert, but I was right where you are 4 years ago. Best of Luck!
Degassing is not an instant thing, even with manual intervention (stirring). As already mentioned, wine will degas with time and kits require manual degassing to meet a short production timeframe.

I appreciate the kit vendors' POV -- if told they'd need to wait 2 years to drink a wine, a LOT less folks would buy a kit. 4 or 8 weeks sells a lot more kits!

The stirring (often stated as 3 minutes with drill-mounted stirring rod, changing direction every 30 seconds) does not eliminate all the CO2. It kickstarts the degassing process into high gear, causing the wine to emit a large amount of CO2 during and immediately after stirring; the wine will continue to emit CO2 for at least a week or two, probably longer. [This is based on observation, not any rigorous testing.]

Contrary to a common opinion, stirring does not introduce any appreciable amount of O2. I've had kit wines go 7 years with no evidence of oxidation -- this makes sense since the wine is emitting so much CO2 during this time that O2 can't get in.

That said, don't degas more than once as it's not necessary. I suspect that if the wine is not emitting a lot of CO2, the likelihood of introducing O2 is much higher.

I now degas all wines. Not because of time saving -- currently I bulk age wines 6 to 12 months. I do it as the gross lees settles faster with the CO2 gone, so I get the wine off the gross lees faster.

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