Using activated charcoal before acid testing

[chris_b]

I wasn't quite sure where to post this question as it might be more general than for wine making. As that's what I was doing, here goes ...

Some of the grapes I grow have dark red juice. When using an acid testing kit, I found it impossible to see the colour change, not even the shade of grey that's talked about.

It occurs to me that I could heat (boil?) the juice sample with activated carbon to remove the colour, but would that change the acidity level as well? My recollection of doing this in chemistry is that the granular carbon does not replace the original colour with a dense black.

Ideas/experiences welcome (before I go and get a load of carbon!)

Chris

[fatbloke]

I wasn't quite sure where to post this question as it might be more general than for wine making. As that's what I was doing, here goes ...

Some of the grapes I grow have dark red juice. When using an acid testing kit, I found it impossible to see the colour change, not even the shade of grey that's talked about.

It occurs to me that I could heat (boil?) the juice sample with activated carbon to remove the colour, but would that change the acidity level as well? My recollection of doing this in chemistry is that the granular carbon does not replace the original colour with a dense black.

Ideas/experiences welcome (before I go and get a load of carbon!)

Chris

Don't remember doing that in school chemistry (though it's a long time ago ).

I only use activated carbon for filtration/purification, I'd actually suggest getting a small/pocket pH meter because it's infinitely easier than trying to look at colour changes on litmus strips.

Plus, I seem to recall reading somewhere that carbon can reduce/affect/mar test results as it's not neutral, even though it doesn't blacken a sample any further, I believe that it's slightly alkali, if anything. Though others might know better than me on that.

If you have a dig around, you can usually find pH meters in the £20 to £30 range that do the job well enough for what we need.

regards

JtFB

[Rich]

Have you tried adding distilled water to the red wine to thin it a little?

It doens't change the acid contents or reading, but should make it easier see the colour change.

I was dubious at first when reading the instructions, and tested it with some white wine. Same results with or without added distilled water. Don[t use normal water, it screws it up.

[rjb222]

Have you tried adding distilled water to the red wine to thin it a little?

It doens't change the acid contents or reading, but should make it easier see the colour change.

I was dubious at first when reading the instructions, and tested it with some white wine. Same results with or without added distilled water. Don[t use normal water, it screws it up.

This is exactly what the testing kit says should be done. just make sure it is distilled water that is used.

[lockwood1956]

Sometimes easier to see the colour change by placing a drop each time onto a piece of white card.

Also using distilled water to dilute the colour will help immensley and not affect the readings.

regards
Bob

[NorthernWiner]

A pH meter makes it very easy to test acidity without having to rely on color change. Simply add sodium hydroxide solution until the pH reads 8.2 and that's your endpoint.

[lockwood1956]

A pH meter makes it very easy to test acidity without having to rely on color change. Simply add sodium hydroxide solution until the pH reads 8.2 and that's your endpoint.

Indeedy,

see here for detail

http://www.winesathome.co.uk/forum/showpost.php?p=29670&postcount=2

[Zebedee]

Whatever floats your boat....

While not knocking anyone who wants to take this hobby to the n'th degree, I class this as a fun pastime and although I wish to learn and increase my knowledge, I have no desire to become an Analytical Chemist.

[chris_b]

Thanks for the comments and advice everyone,

I have a pH meter - £15 from ebay of chinese manufacture - and I've set it up with some buffer solution, though it was within 0.1 out-of-the-box. So I relied on this when correcting the acidity of the wine that was too dark.

I'll try the diluting method and see how it goes.

I suppose the real question is: With respect to the taste/style of the wine, rather than the chemical exactitude , what is the difference between measuring "acidity" by pH or by TA in ppt sulphuric acid? It's a lot easier to dunk a pH meter in the wine than go into chemist mode.

Chris