how to use a hydrometer for newbies

[cpfan]

I am new to wine making and have a question. During the primary fermentation (aerobic) I understand the yeast is consuming the sugar but not making alcohol so the SG will be going down but without the alcohol? Is that correct?
Because of this I have been measuring the SG again just before I put into demijon and start of the anaerobic fermentation (when yeast does convert sugar to alcohol). I have added sugar at this stage to get the SG to 1.100.
I think I must be wrong as I seem to be adding a lot of sugar.
Main question therefore is - is the starting SG the SG of the must or the SG just before it is added to the demijon with airlock?
Many thanks for help

The starting sg is the reading prior to pitching the yeast. For example,

Mix up ingredients, get sg 1.082. Pitch yeast.
Start of anaerobic (how do you detect this anyway? ). 1.050
End of fermentation. .992

Alcohol is (1.082 - .992) * 133 = .090 * 133 = 12%

Note that the 1.050 is not used anywhere in the calculation.

Is the yeast making alcohol during the aerobic fermentation? I always thought so.

I think that very few winemakers worry about the difference between aerobic & anaerobic fermentation. I understand that the yeast needs oxygen to get started, so I stir vigourously in order to include oxygen throughout the must. When is the O2 used up? Don't know, don't care. I doubt that it is when I transfer to a secondary vessel (eg carboy) to complete fermentation, because the sg is below 1.010 at that point.

BTW, please do not be afraid to start a new thread. Your question seems only barely related to this thread.

Steve

 

[tucson]

Jalapeño wine, before pitched yeast 1.110 added yeast and fruit then went to 1.090. Dried to .992 and back sweeten to 1.005. What would the % be?

 

[cpfan]

Jalapeño wine, before pitched yeast 1.110 added yeast and fruit then went to 1.090. Dried to .992 and back sweeten to 1.005. What would the % be?

Starting sg 1.110, final sg .992, so %alc is (1.110 - .992) * 133 = .118 * 133 = 15.7%

However, it appears that you added fruit after taking the initial sg. In general, fruit means more sugar, so higher alcohol, but impossible to calculate. However, if you meant that the jalapenos were the fruit then I don't think there's much sugar content, so the 15.7% is probably pretty close.

Steve

 

[tucson]

Yes, the only fruit was 15 jalapeños and man-o-man does it have a bite in back of the throat, the mint and apple juice were a nice touch.

 

[JoyofWine]

Can someone please clarify the correct readings of the notches between .990 and 1.000?

Like if the reading is a notch above 1.000 would that be .998?

 

[jimmyjames23]

Each notch is worth 2.

 

[jimmyjames23]

Can someone please clarify the correct readings of the notches between .990 and 1.000?

Like if the reading is a notch above 1.000 would that be .998?

That is correct.

 

[JoyofWine]

Thank you!

 

[sdelli]

Great pics Jim! Looks good. Only thing to make sure gets added is what Wade left a link to..... If you don't read it correctly it still is not an accurate piece of equipment. Must read it at the bottom of the curve.....

 

[Skyshark93]

Thanks for this post. I am a newbie with wine making, thus this helped me out so much. I had a lot of question about the hydrometer. I now understand. Thank you.

 

[Elmer]

I have my hydrometer for atleast 7 years.
During that time I have never got a reading above 1.000.
I know wine should read above 1.000 to .995, but it had never happened.

The guy at the local wine shop had always told me that since I usually kept my wine in a colder spot (65 degrees) it would never read above 1.000.

So I finally got around to testing my Hydrometer in water and it read 1.002 (1st notch below 1.000).

in my last 2 batchs I had transfered to carboy and stopped fermentation when I got atleast 1 week of nothing but 1.000 reading.

Given how my Hydrometer reads in water, is it safe to assume that my 1.000 is someone elses .995?

 

[dralarms]

Nope, .998 would be closer to correct. I'd replace that bugger.

 

[Elmer]

Nope, .998 would be closer to correct. I'd replace that bugger.

I am stopping by the wine supply store on the way home.
BUt in the 7 years of making wine, I have never had it go to .998!

But I will take your advice!

 

[Elmer]

I am stopping by the wine supply store on the way home.
BUt in the 7 years of making wine, I have never had it go to .998!

But I will take your advice!

So I stopped by my wine supply store, but the owner told me not to replace the hydrometer because it was probably just calibrated off a little.

Wouldnt you know it, I get home and bump into my supply rack and that bugger fell and smashed to the ground!

So I will be replacing it after all!

 

[moesagoodboy]

So I stopped by my wine supply store, but the owner told me not to replace the hydrometer because it was probably just calibrated off a little.

Wouldnt you know it, I get home and bump into my supply rack and that bugger fell and smashed to the ground!

So I will be replacing it after all!

Seven years is really good. My first one only lasted 5 months. Verify the calibration against distilled water. And buy a second one for reserve, you might be on losing streak.

Joe

 

[Elmer]

Bought a brand new Hydrometer. Tested it on both tap water and filtered water out of my fridge. Below are the results.
Once again, in 7-8 years I have never been above 1.000.
Could it be my altitude? My water?

Filtered


Tapwater

 

[robie]

Temperature is a factor and should be considered. Most hydrometers come with a compensation chart, based on the calibration temperature of the specific hydrometer. Some are calibrated to 60F, some to 68F and maybe even something else, so check your hydrometers documentation.

Also, tape water is almost always going to have a higher SG than distilled water. You should check it in distilled water only, if you want a truly accurate reading.

When you insert the hydrometer, be sure to spin it to remove all the tiny bubbles that might have formed on it. They can affect the reading.

In the end, the actual reading is not that terribly important as long as the wine ferments to the 1.000 mark or lower (.995 to .999). If it does get into that range, once the SG reading has not changed for 3 days in a row, fermentation is finished.

As far as calculating ABV from the hydrometer readings, it is only a close estimate anyway.

 

[x_diver]

Distilled water has a SG of 1.000. So how is it that wine can ferment to a SG of less than 1.000? The tables I see online indicate that a SG of 1.000 has almost no sugar.

I ask because I am new to wine making and my first batch of Welch's has a SG of 1.000 - yet it is still bubbling.

 

[FABulousWines]

I think it is because alcohol has a lower SG than water. Someone please correct me if I am wrong.

 

[Rocky]

FAB, you are absolutely right. Wine can go below 1.000 because it contains ethyl alcohol which has an SG of 0.787.