When to add Tannin?

[pete1325]

Hi all, four days in to primary and I was considering adding (grape) Tannin to my Cab. When is a good time? It's in dry form and and it says 1/8 to 1/4 teaspoons per gallon. Thoughts?

 

[robie]

Different tannin products can be added at different times. Some upfront; some anytime; some after fermentation is complete.

Look up the instructions on the internet for your specific tannin. It should let you know. Make sure you follow the instructions.

 

[ibglowin]

Tancor Grand Cru is a post fermentation tannin. You want to add it a full 30 days before you filter/bottle as it will leave a small residue behind if you don't.

 

[Flem]

Depending on the Cab you have, you may already have enough tannin in it. I would suggest you taste it first. IMHO

 

[djrockinsteve]

Just for your information if you add tannin it will throw off your sulfite readings later on if you take a sulfite test. You will get a false positive. Generally once tannin is added you don't take it out easily.

 

[pete1325]

Thanks, I'll hold on the Tannin for now and see what it taste like later. I heard/read somewhere that you can add it later, in the bulk storage stage. True?

 

[BobF]

Generally speaking, tannin can be added any time. There are pros/cons either way. I usually add 1/2 of what I think I'll want pre-ferment and make small adjustments along the way.

One advantage to early addition is that tannin helps protect the wine and preserve color. The disadvantage to early addition is that it's not as easy to tell how much you need/want when the wine is young - the opposites being the pros/cons of later additions.

This is why I add some early and tweak later.

** I'm not sure how this post ended up in this thread. If a mod would move it, I would appreciate the gesture! It belongs in "When to add tannin"

 

[Jwatson]

How does the addition of tannin such as Tancor Grand Cru throw off sulfiter readings and for how long?

 

[BobF]

How does the addition of tannin such as Tancor Grand Cru throw off sulfiter readings and for how long?

I would like to learn about this as well. Any references would be greatly appreciated.

I use A/O for testing so2 levels. Maybe tannin interference is specific to testing methods?

 

[djrockinsteve]

I have read this and experienced it when I went to check my sulfite levels. It was off the chart and I hadn't added that much. I believe natural tannin doesn't effect it. I'll try to find the reading and post it.

I don't know if there is a period of time where added tannin doesn't give a false positive.

 

[BobF]

I have read this and experienced it when I went to check my sulfite levels. It was off the chart and I hadn't added that much. I believe natural tannin doesn't effect it. I'll try to find the reading and post it.

I don't know if there is a period of time where added tannin doesn't give a false positive.

What method do you use to test?

 

[BobF]

I found this in the titrets instructions:

Test Method​

The Sulfite in Wine Titrets

®1 test is based on the “Ripper”

chemistry which employs an iodide-iodate titrant in an acid
solution and a starch indicator​

​

2,3,4. The “Ripper” chemistry is

used as a screening method throughout the wine making
industry for determining the sulfite content in wines. Results are
expressed as free SO​

​

2. Results for this test kit are acceptable

for dry white wines although they can have an error of up to 10
ppm. This test kit is not recommended for use with red wines or
white wines containing ascorbic acid or tannin. These wines
often give false high test results. As a rule, a test result of greater
than 40 ppm free sulfite for any wine should be considered
suspect and an alternative sulfite determination method should​

be employed.


Reading through many forums -too many places to reference- the general consensus is that A/O and the Vinmetrics probe are not impaired by tannin (or ascorbic acid).

The discussions lead me to believe that tannin interference is specific to the chemistry used in the Ripper SO2 testing method. This is the method used by Titrets.


​

 

[ibglowin]

Wait a minute.

The Vinmetrica probe works via the "Ripper" titration !

The Vinmetrica SC-100 is a simple and robust SO2 meter that provides high accuracy in measurement of free and total sulfite
( SO2 or sulfur dioxide ) levels in wine. Based on the reliable and widely-used Ripper titration, the SC-100’s amperometric principle allows trouble-free detection of the sulfite endpoint in wine and musts, red or white.
Theory of operation: The Ripper titration is based on the quantitative reaction of the SO2 with iodine (generated during the titration) which oxidizes the SO2 in the sample under acid conditions. When all the SO2 is titrated at the endpoint, excess iodine appears in solution. This is detected as current with the electrode and signalled by visual and audible indicators. The endpoint is much more sensitive than the starch endpoint commonly employed for Ripper titrations, and it is sharp and clear, even when titrating red wines and musts. From the known concentration of the titrant and its volume required to reach the endpoint, the free SO2 is simply calculated.

 

[ibglowin]

Found an intersting link with some more info on the ripper titration and its associated chemistry.

Seems the iodine titrant will react not only with SO2 but also with aldehydes and ketones (which are very similar in chemistry) causing a false high result.

Must be some floating around in all the flavonoids contained in the Tan'cor.

 

[BobF]

The 'interesting link' references an SO2 paper I snagged a copy of some time ago. It's all coming back to me now ... the reason I didn't go for the probe.

For me, A/O with the sample in an icewater bath is the way to go!

 

[djrockinsteve]

Okay here it is. If you read the card that comes with the titration test kit, on the back side halfway down it reads and I quote..

"This test kit is not recommended for use with red wines or white wines containing ascorbic acid or tannin. These wines often give false high test results."

That is exactly what I had experienced, a reading so high it was beyond the test kit ampule.

 

[BobF]

Steve - That's what I posted above. The caution is specific to Titrets/Ripper SO2 testing.