K Bicarbonate to reduce TA

[Frank the tank]

HI all,

I have a barrel of California Cabernet Sauvignon that I was a little heavy handed with the Tartaric Acid addition at crush. It is a 23 vintage and has gone through MLF. Its current specs are pH 3.46 and TA of 7.15.

I am doing a bench trial with K Bicarbonate to test the wine at a few different addition levels to reduce the TA. The samples with additions have been in the fridge for 10 days and I will sample at 14 days.

My question is:
Can I let the wine warm to room temp to decant and taste or will that cause the K bitartrate crystals to dissolve into the wine by any degree. Do I need to decant with the wine at the cold temp to get an accurate taste test / reading? I ask this also with the addition and racking of the full batch in the barrel in mind.

Thanks for weighing in with your experiences.

 

[ChuckD]

I can’t answer your question directly, but those numbers don’t sound especially high. Have you tried a little back-sweetening to balance the acid?

I have a 100% rhubarb juice wine that did require acid adjustment with bicarbonate. What I did was load up a half gallon of the wine with as much bicarbonate as it could dissolve… I kept it in the fridge and would shake it up every day. I then racked off the clear basic wine and used that to do bench trials and to adjust the whole 6-gallons of rhubarb wine.

 

[winemaker81]

My understanding is that the crystals do not dissolve easily, so the wine warming up shouldn't have much effect. However, I'd rack off the crystals before tasting, just to be sure.

What does the untreated wine taste like? It is possible that simply cold stabilizing the wine may reduce any acidic taste enough. K-carbonate can produce a chalky taste, so I'd avoid it, if possible.

 

[Rice_Guy]

I don’t see where you are, my Wisconsin point of view would be to have it in the garage at -2C to crystallize as much bitartrate as possible. With northern hybrids 0.7% TA is about as good as we can get.
Tannins are part of the acid like taste profile. ,,, one gram of tannin tastes similar to twenty five grams of a chemical acid. Tannin will naturally polymerize over time and give a smoother flavor. In tasting are you reacting to acid which saliva washes off the taste buds by thirty seconds, or are you reacting to skin tannins which give a roughness in the mouth, and on young wine may last two minutes in the mouth?

Two bench trials to evaluate the source of flavor. 1) neutralize the wine to pH 7 or 8.2 and then taste. What is left will be the flavors the tannins produce. 2) pull the tannin out with egg white fining. What is left will be the portion of flavor left which acids contribute.

 

[wood1954]

I would leave it alone. You could end up with a lower TA but a much higher ph. I’ve used a lot of potassium in the past and sometimes ended up chasing numbers which made for awful wine. Cold stabilizing or just aging will help drop acid.