Having pulled a considerable amount of the little bit of hair I've got
left out yesterday trying to test acid , I found out that from one of
the suppliers that I deal with , that the sodium hydroxide that LD
Carlson bottled up isn't right , so if your numbers are wacked , maybe
your sod. hyd is suspect.

On Sep 25, 10:20 am, wrote:
> Having pulled a considerable amount of the little bit of hair I've got
> left out yesterday trying to test acid , I found out that from one of
> the suppliers that I deal with , that the sodium hydroxide that LD
> Carlson bottled up isn't right , so if your numbers are wacked , maybe
> your sod. hyd is suspect.

I've given up on using NaOH. I'm finding consistently reliable
readings with the acidometer test kit. It's easier, cleaner, less
measuring, etc.

Lee

I think there was a bit of a flap over that same issue two years or so
ago. Instead of being 0.2N NaOH solution, what was in the acid test
kits was nearly 0.4N, so all the acid measurements indicated there was
about half the actual level of acidity. The LD Carlson folks were
properly apologetic, claimed their supplier had messed up. But that
wasn't much satisfaction for those who had added lots of unnecessary
acid to their wine, based on bad measurements.

I decided at that point to make my own NaOH reagent, so I spent about
$10 and got a lifetime supply of NaOH crystals. 0.2N works out to 8
grams per liter, and a liter will last me a whole season or more. So
my couple of pounds of reagent should last me for about another
century or so of winemaking, assuming I keep it dry. :-)

Doug

So
> my couple of pounds of reagent should last me for about another
> century or so of winemaking, assuming I keep it dry. :-)
>
That is the key, it's hygroscopic. I have a friend who is a chemist
and he said that was it's biggest drawback, it sucks in moisture like
a sponge...

Joe

Joe Sallustio wrote:
> So
>> my couple of pounds of reagent should last me for about another
>> century or so of winemaking, assuming I keep it dry. :-)
>>
> That is the key, it's hygroscopic. I have a friend who is a chemist
> and he said that was it's biggest drawback, it sucks in moisture like
> a sponge...
>
> Joe
>
>
Yep, and if you want to dry it out, you have to bake it for about 24
hours at 125C (about 250F) in a nitrogen purged oven. Not many of us
have one of those at home.

Gene

On Sep 27, 2:17 pm, Joe Sallustio > wrote:
> So> my couple of pounds of reagent should last me for about another
> > century or so of winemaking, assuming I keep it dry. :-)
>
> That is the key, it's hygroscopic. I have a friend who is a chemist
> and he said that was it's biggest drawback, it sucks in moisture like
> a sponge...

It will not only absorb moisture, it will also suck up carbon dioxide
from the air to form sodium carbonate. That will also throw all of
your calculations off.

You could, however, standardize your solution by testing the amount of
acid in a known mass of tartaric acid, and fix your calculations that
way.