Titration test

[sjo]

I originaly posted this in another thread.


I got my first batch of peach (canned) wine going. SG 1.085 I let must sit for day with pectic enzyme then added yeast. 6 days later hydrometer was reading .88. Seems to have fermented kind of quick.
I have a question on the titration test. My initial reading before fermentation was .7 when I racked it a week later it was over 1. How does that work? Will I need to bring it down?

The first test done colored the must from top of the vile down.
The second test colored the must from the bottom up. Both times the must changed colors in layers as I added the sodium hydroxide. Is this correct? I was expecting the entire vile to change colors as hydroxide was added going from a light to a dark color.
Thanks
Scott

 

[Luc]

Did you mix after dropping the solution in ???

You need to mix it thoroughly by holding the
test cylinder upside down. Otherwise the color
change will not work well.

Did you degas the wine ???
CO2 is an acid and can give off readings.

I did an essay on titration with photo's:
http://wijnmaker.blogspot.com/2008/11/zuurmeting-01-measuring-acidity-01.html
That might help.

Luc

 

[sjo]

Luc,
I had read your blog on the titration test, and did not get quite the same results. I was thinking maybe there was a difference in the type of test.

My instructions said to agitate cup until a slight color change is noted. I did not mix with a foreign object but did shake up the cup a little.
Each time I added theneutrailizer it would color a little layer of liguid in the cup working it's way down to the bottom of the cup. It took 7 cc of souloution to get to the bottom so I figured that was the final result.

I did not degas the wine on the second attempt and when the test was done it changed color in layers from the bottom to the top. 10 cc of soloutions was required for the change.
I will degas it and try again.
If it is to high will calcium carbonate take care of it?

Scott

 

[sjo]

I just finished the titration test again. Worked out betterwith results between .5 and .6 . It is a litttle sour though. What causes that and will it get better on it's own?
Thanks
Scott

 

[Luc]

You experienced what I described
A wine that is not degassed will have a higher acidity (at your case 10) as a wine that is degassed.

For a white fruitwine an acidity of .5 to .6 is right in the ball-park.
Even .7 would not be bad, depending on alcohol and body of the wine.

If a wine has high acidity and no body aim for a low alcohol. Otherwise you will be making something that will taste like rocket-fuel.
When the wine has a low acidity and a lot of body, you can give it a bot more alcohol.

Generally a fruit wine should be in the 10-11% alcohol range.

Luc