How good a chemistry lab do you need?

[Boatboy24]

I got some more details from Harford Vineyard over the weekend regarding their Chilean buckets. I was told that they are supposed to be balanced when they arrive. But over the years, they have seen them off from time to time. Seeing as how I've all but officially decided to get some buckets, I'm now trying to make sure I've got the bases covered to adjust as needed when I get my precious little buckets home. I expect to have TA, pH, and Brix/SG measurements from the vendor and imagine that I should confirm those myself. Then what? What sort of targets should I be aiming for, and what sort of chemicals should I have on hand if I'm off target?

I've only been making kits for a year now, but this move to juice makes me feel like a total rookie again. Thanks for your input!

Jim

 

[JohnT]

For PH, a good target is 3.35 to 3.5.

For TA, A good target would be .65 g/l for reds, .70 g/l for whites/fruit wines

For brix, well that can vary greatly from grape to grape. For the most grapes, a brix reading anywhere from 20% to 26% is to be expected. If you are getting bucket juice, I would advise against any sugar adjustment. Just go with what you have.

Adjust acid using tartaric acid (to lower your PH) or k-bicarb (to raise your PH).

As with kits, k-meta, sorbate, etc are always handy to have as needed.


Note: The above is only my opinion. Others might disagree.

 

[Turock]

Don't use potassium carbonate to adjust musts pre-ferment. Potassium carbonate is only for tweaking PH post ferment---not moving it several tenths. Also, potassium carbonate can damage the nose and delicate flavors in some wines and should not be used at all.

Use calcium carbonate for increasing the PH if needed. Tartaric acid for grapes to lower the PH--but acid blend has many uses,also. Sometimes the citric acid in acid blend is a nice addition to some musts that need more acid bite.

It's impossible to tell you a standard PH--depends on the wine. I think you're wise to take Ph readings on bucket juice. We never take anything for granted---we test everything, no matter what it is--even Alexander's concentrate. Your wines will be more balanced and you'll become a better winemaker by testing and adjusting PH. PH can really influence the flavors that come out in the finished wine. Acid adjustment always yields a better result when done pre-ferment rather than post ferment.

 

[GreginND]

but acid blend has many uses,also. Sometimes the citric acid in acid blend is a nice addition to some musts that need more acid bite.

I would not recommend acid blend to be used - ever. Citric acid is not stable to microbes. This is particularly a problem if you do MLF. ML bacteria will convert citric acid to acetic acid (vinegar).

 

[Boatboy24]

Thanks all. I'm looking forward to stepping up my game.

Jim

 

[Polarhug]

I would not recommend acid blend to be used - ever. Citric acid is not stable to microbes. This is particularly a problem if you do MLF. ML bacteria will convert citric acid to acetic acid (vinegar).

What is your recommendation for increasing an acid if needed?

 

[GreginND]

What is your recommendation for increasing an acid if needed?

I would only use tartaric acid for grape wines. I actually use it for other fruits too.

 

[Turock]

You would never use citric acid if you're going to do an MLF--that is true. But to say acid blend is never a good choice is putting absolutes on the thing and you can be missing out on the tools available to winemakers. We always use acid blend on our Niagara wine--it turns out beautifully. Citric acid by itself is often used post ferment to add a little "zing" to whites.

 

[GreginND]

I did not say it is never a good choice. I said that I would not ever recommend it. Using citric in any grape wine risks microbial instability.

And in commercial grape wine production citric acid additions are not allowed.

 

[Turock]

Who said anything about commercial wines? I still disagree with you because experience with it is everything. I don't always agree with what every white paper has to say on a subject when my experience over 1/4 of a century says otherwise.

 

[Polarhug]

And in commercial grape wine production citric acid additions are not allowed.

That is what I LOVE about the forum. Learning so many new things, & new ways to do things every day!

 

[GreginND]

Sorry - my bad. I just looked up the TTB regulations on acid additions. It does say you may add citric acid but you can only add it after fermentation. You cannot add citric acid prior to fermentation.

For berry wines the TTB only allows citric acid be used.

The regulation on acid additions can be found here:

http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=b7f9f236991b6c5fbfc2934633c089f2&rgn=div5&view=text&node=27:1.0.1.1.19&idno=27#27:1.0.1.1.19.6.343.8

 

[skyrat]

Greg, Maybe I am missing some points here but in reading this thread maybe you are missing a point as well?? I think you missed Turocks point.

A lot of folks on this forum are "Amateur" IE: non commercial winemakers and as such are not subject to TTB rules. They are a good guide for us but we can do anything we like as far as additions of Acids / types. True we must consider the consequences of when, what and how to use Acids BUT.......Acid Blend does add certain characteristics to wines and in that we are free to experiment. I have quite a few different berry wine recipes that I use Acid Blend in. No one has complained yet.

 

[Turock]

I agree with you, skyrat. Tartaric is the softest tasting of the acids. It depends on what you're working with and what your tastes are. After all---this is why we make our own wines---so we can tweak things and come up with flavor profiles that many of us don't find in commercial wines. Very often you want more tartness because it brings out other characteristics in the wine, as you mentioned.

Some things are said, within a forum, that are talked about with hard and fast rules that really don't exist. This limits new winemakers into having less tools to work with when they really should be experimenting in order to understand something like the uses of different acids.

The good thing about having these kinds of exchanges within a forum is that it gets people thinking and it causes people to do a little more research and get more info into what was said. This hobby can require a lot of study and you don't think about some things until a difference in opinion comes up. Everyone ends up benefiting from a little more research--so it's all good.

 

[GreginND]

Thanks Guys. I don't mean to argue. I was simply pointing out that citric acid can have a problem with microbial stability. I brought up the TTB regulations because this is one of the rare cases where one of their regulations is actually based on a good reason.

I do agree that rigid rules without explanations are not good for new winemakers to learn. But I also think offering suggestions without informing about potential consequences of them may also be a problem for them.

In any case, I hope our discussion here has helped to inform people and I do hope they experiment on their own. That is the fun of winemaking!

 

[Turock]

Greg--I don't understand the idea of citric acid having microbial instability. Did you read a white paper on this? I'd like to read it.

I DO know there are molds that like citric acid. But within a wine you not only have the PH controled in a certain range, but you also have alcohol content and these 2 together along with SO2 prevent any microbial activity. It has been said that not even a human patholgen can grow in such an environment.

Some winemakers even use citric acid along with meta for santitizing. So I'm just not sure of the science on this and would like you to enlighten me.

 

[ibglowin]

The major disadvantage of adding citric acid is its microbial instability. Bacteria can use citric acid in their metabolism, thus any citric acid added may just be consumed by bacteria, promoting and or fueling the growth of unwanted microbes.

If citric acid is used in a wine it should always done after primary alcohol fermentation has been completed due to the tendency of yeast to convert citric into acetic acid.

 

[Turock]

So what you're saying is there is a difference between citric acid itself and the small amount of citric acid in acid blend?

 

[ibglowin]

Citric acid is citric acid, doesn't matter if its in a blend or by itself.

 

[GreginND]

Yes, you're right. Yeast will metabolize citric acid into acetic acid. And ML bacterial will convert it to diacetyl. There are a lot of biochemical pathways for degradation of citric acid. Again, it is much more of a problem before and during fermentation than it is after the wine is finished and stabilized.

The original poster in this thread was talking about adjusting pre-ferment must if I am not mistaken.