SG Reading Not Stable

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JohnRingo

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Hi all, I am new to wine making and new to the forum. Currently I am making my first batch. I have a Master Vintner kit and the instructions say during primary fermentation to add yeast nutrient when the SG reaches the range of 1.04 to 1.05. When I used the thief to put some fluid in the test tube it seemed as though there was a lot of gas dissolved in the wine. After placing the hydrometer in the tube the initial reading was about 1.045. But gas appeared to fizzing out of the wine and the hydrometer reading was increasing fairly fast. Should I use the initial reading or wait for the reading to stabilize?
 

KCCam

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Welcome to WMT. The hydrometer rises because the bubbles are attaching to the glass, and giving it more buoyancy. Lift the hydrometer out of the wine (pops any bubbles on the surface), put it back in, and spin it. Once it stops bobbing up and down, get a reading. Do it again. You should get a really good idea after a couple attempts. It's not critical.
 

Scooter68

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Best description of what is going on would be to take a bottle of carbonated soda (Pop, Coke etc), open it and drop in a straw - watch and very soon the straw with start to rise out of the soda.
That's what's going on with the hydrometer. Since it's much heavier than a straw the amount of change is much less but it can easily raise it .002 - 004
 

Lukaswine

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Welcome to WMT. The hydrometer rises because the bubbles are attaching to the glass, and giving it more buoyancy. Lift the hydrometer out of the wine (pops any bubbles on the surface), put it back in, and spin it. Once it stops bobbing up and down, get a reading. Do it again. You should get a really good idea after a couple attempts. It's not critical.
Thanks for the tip. I will be making another kit today and I’m always concerned about incorrect readings when bubbles exist.
 

winemanden

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Thanks for the tip. I will be making another kit today and I’m always concerned about incorrect readings when bubbles exist.
About readings discrepancies. I used to work in a Laboratory and was watching a labourer laying some paving slabs. I said to him, 'I like to watch someone doing accurate work. We work to 10,000th of an inch here. 'You'd be no good doing this then mate,' he replied. 'On this job, you've got to be spot on!'
 

Scooter68

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You can try giving the hydrometer a spin as you release it in the testing tub. Only problem is getting dizzy trying to read a spinning hydrometer. :d
And by the time it stops spinning, bubbles start to collect again.
BUT, on the upside, readings taken during fermentation don't have to be spot on - you're just taking a snapshot of where it is at the moment. At the end of fermentation you will still have that CO2 bubbling but normally you can still get a good enough reading to determine if the ferment is over. The difference between .994 and .992 - does it really matter? Unless the reading the day before was .996 or .998 I'd say record it and check again the next day. I just look for a reading that appears not to change for 3 days in a row. If you skip a day or add in one more day, it's really not that critical. I just wouldn't leave a bucket of fermented must with just a cloth cover after I'm pretty sure the ferment is done. That's one of the reasons folks will move a ferment into a carboy when the SG is at 1.010 or lower - to get an airlock on it. Otherwise just wait one more day and check again. If your ferment is in the range of 1.050 - 1.020 I would certainly not sweat a change upward of .002 or even .004, just either take it again or take in the next day.

If Extremly precise SG readings were that critical - you would see a lot more digital/electronic hydrometers. They're out there but not that much demand because in wine making it isn't that critical.

Look at a lot of bottles of alcholic beverages. The phrase "ABV 13% Approxmately" is not uncommon.
 

KCCam

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Thanks for the tip. I will be making another kit today and I’m always concerned about incorrect readings when bubbles exist.
I always tend to overdo it. Take @Scooter68’s advice. When the hydrometer is hardest to read accurately is when it matters the least.
 

Lukaswine

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You can try giving the hydrometer a spin as you release it in the testing tub. Only problem is getting dizzy trying to read a spinning hydrometer. :d
And by the time it stops spinning, bubbles start to collect again.
BUT, on the upside, readings taken during fermentation don't have to be spot on - you're just taking a snapshot of where it is at the moment. At the end of fermentation you will still have that CO2 bubbling but normally you can still get a good enough reading to determine if the ferment is over. The difference between .994 and .992 - does it really matter? Unless the reading the day before was .996 or .998 I'd say record it and check again the next day. I just look for a reading that appears not to change for 3 days in a row. If you skip a day or add in one more day, it's really not that critical. I just wouldn't leave a bucket of fermented must with just a cloth cover after I'm pretty sure the ferment is done. That's one of the reasons folks will move a ferment into a carboy when the SG is at 1.010 or lower - to get an airlock on it. Otherwise just wait one more day and check again. If your ferment is in the range of 1.050 - 1.020 I would certainly not sweat a change upward of .002 or even .004, just either take it again or take in the next day.

If Extremly precise SG readings were that critical - you would see a lot more digital/electronic hydrometers. They're out there but not that much demand because in wine making it isn't that critical.

Look at a lot of bottles of alcholic beverages. The phrase "ABV 13% Approxmately" is not uncommon.
This helps . Thanks!
 

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