My woes with testing TA

Franco, It sounds like you have a supplier problem rather than a sodium hydroxide problem. I have ordered sodium hydroxide from "Presque Isle Wine Cellars" (

) for many years and I have found them to be very reliable and helpful. Lum Del Mar, California, USA

Thanks Lum. I just ordered from Presque Isle a bottle of 0.1N NaOH and another of 0.1N potassium acid phthalate to standardize.

Franco,

That was exactly what I was going to suggest, Presque Isle and get the standardizing solution. I have been buying it for years from them. I always standardize the solution first. Mine sits in a 500 ml squeeze bottle for no longer than 6 months as I use it up. It's never been off more than 0.0015N (+/- 1.5%) initially, usually right on. Over time it can fade as you well know, I pitch it if it gets to 0.09N. By that time it's only a few ounces and it rarely happens, I end up going through a lot of it testing for others.

I have bought it at Fisher Scientific too, but it's about 5 times more for theirs. It's dead on though.

Joe

Franco, One other thing. Don't forget to heat the sample first, it does affect the TA end results. You don't have to boil but I do. I put 50 ml in a microwave for around 30 seconds. As soon as I see boiling I cool and add distilled water back to 50 ml. It makes a difference.

I never see any references to prepping like this for pH measurement. Since I want to remove the CO2 in the real wine too, I test the pH of this sample, it can be different by 0.1 pH units. I guess what I should do is measure one last time right before bottling, it may be a good indicator of CO2 saturation.

I rack pretty gently so sometimes have more CO2 left in the end than I prefer, it's a pain to degas. I'm starting to rack the reds more roughly, both to degas and expose it to a little bit of air. I used to use two racking canes on both reds and whites, one in the receiving vessel to let the wine trickle in from the bottom up. I don't think that makes sense anymore at least with reds.

Joe

Another option for getting the solution - a friend of mine makes his own from lye he gets from a hardware store. You can make it fresh, as much as you want when you need it. I don't know the ratio to water to make up the 0.1N standard, but I can ask.

Pp

I assume that was and LD Carlson kit. There was a bunch of discussions over on winepress about it and they have since recalled those kits.

Franco wrote:

Franco - A couple of months ago there were similar posts on another winemaking forum, and it turned out that the NaOH solution supplied with many of the L.D.Carlson acid test kits in the past year was significantly stronger than it should have been. If the kit was designed for 0.2N NaOH, it seemed like the actual strength was around

0.35 N or so -- close to twice as strong as it should have been, resulting in erroneously low acid measurements. Carlson discontinued sales of their product (which they don't manufacture, they just distribute) until they could either assure better accuracy, or find another supplier. I'm not sure whether they have resumed distribution of these kits yet.

Carlson seemed to be trying to handle the whole thing responsibly, but they have no way to contact all the folks who bought their kits over the past year or more, and several winemakers who had added a lot of acid to their wines based on these bad test results were pretty irate about the whole thing.

Here is a URL to the thread discussing this problem, including comments from Rob Kight, General Manager of L.D. Carlson.

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So far as I have heard, the problem did not affect other sources (e.g., Presque Isle), but I think L.D.Carlson does sell a lot of these kits through local homebrew outlets, so I'm sure it affected a lot of folks, many of whom may not know it yet. :-(

Doug

Yes, I have the Carlson kit. Piece of shit. I'm gonna send them my very tart blueberry wine and ask them to shove it up their asses. I've learned a lesson. Maybe if I cold stabilize it and get a lot of tartaric acid to precipitate I can salvage it.

You may want to blend it with something else, that really works well.

I doubt you can pull much more than 1g/l out cold stabilizing. If the pH was at 3.2 or lower you could try calcium or potassium carbonate but

3.35 is not bad. Maybe do both, some potassium carbonate to reduce it 1g/l and then cold stabilize. A little sugar goes a long way on tart wine too.

Don't do anything until you get good chemicals. A tart wine will keep practically forever, you could have worse problems...

Joe

I'd like to know more about how he does this and why. Is he doing this to ensure that he always has fresh solution? To save money? Some other reason? How reliable are the results?

Erroll

Both money and reliability of results although reliability is by far a bigger concern - his argument was that people get cheap in wrong places, use expired solutions to save money and end up with unbalanced wine as a result.

The results should be very reliable - the solid form is way more stable if stored properly and the cost is minimal so there is no incentive to keep outdated solution. I've just found on the net that 0.1N solution is 0.4% NaOH to 99.6% water by weight, so it would take only about 0.5g NaOH to make the 120 ml or so batch that comes in the acid testing kits.

I'm happy with the premade solutions I'm getting and don't have problems with the results, so I haven't bother, but it might be a good alternative for people who do have problems or can't get premade solutions locally.

Pp

If by "solid form" you mean pure NaOH, I think that it is extremely toxic. A biologist friend of mine told me that he got dizzy handling NaOH pellets even though he was wearing all protective gear and he had a extraction hood pulling the fumes out of the room.

Lye is sodium hydroxide, we used to buy it in 55 gallon drums and took no extraordinary precautions other than to keep it away from water, it's exothermic. We used to use it on 100 year old drains (shudder). We wore gloves and eye protection and just dumped it down slow drains. I'm surprised that is still legal but if lye is still available in hardware stores I can't imagine another use for it, it's pretty reactive stuff.

One problem with making up your own solution is minor but should be mentioned, it's very hygroscopic. If you buy some and just weigh it out to use it you can be off a bit because once opened it absorbs moisture. I do think 4 grams in one liter is correct for 0.1N but have never made any myself. (I got this from a chemist, I'm not one so can't speak with authority on the subject.)

It's always a good idea to calibrate it no matter how you get it.

Joe

Franco wrote:

I got curious and did a little poking around. It looks like people who make their own soap use lye, and it's for sale at place like these:

It may not be commonly available in hardware stores anymore. A drain cleaner called Red Devil, which was 100% lye, has been discontinued.

It looks like Presque Isle sells 16oz of NaOH solution for roughly the per pound price of dry NaOH. How many grams in a pound again? Isn't that enough to make about 100 liters of solution? Might be worth doing.

Erroll

If I were going to make my own I would get it from a chemical house like Sargent Welch or Fisher Scientific but you are right, this is incredibly cheap. Fishers is better than 97% pure but sells for $40 a pound. It's still cheaper if you have an accurate balance.

Joe