SO2 Testing

[Wade E]

I think thats an old thread Rob and a few members were in on that!

 

[roblloyd]

I was sort of asking if anyone wanted to start a group buy. I could do the leg work if there is interest.

 

[BobF]

The thing about the More Wine A/O rig is the cost of the 25% Phosphoric Acid. Not a problem for me as I have other sources.......

But once you run out where do do you get refills? (Robie?) The reorders from More Wine are quite expensive.

The A/O rig works great and is the defacto analysis for wineries.

piwine has phosphoric. I got a liter of 75% from St Louis brewing - $13. That makes 3L of phosphoric for SO2 testing.

I've also used 10% (25ml instead of 10ml) and it works fine.

 

[ffemt128]

piwine has phosphoric. I got a liter of 75% from St Louis brewing - $13. That makes 3L of phosphoric for SO2 testing.

I've also used 10% (25ml instead of 10ml) and it works fine.

http://piwine.com/catalog.html?page...e=flypage.tpl&product_id=16166&category_id=31

There is the link for it.

 

[BobF]

SO2 probe vs A/O

I'm not knocking those that bought the probe, but *I* decided to go with A/O b/c a) the SO2 probe is new tech, b) it *still* requires solutions and titration, and c) probe life is and replacement cost are unknowns at this point.

If the SO2 probe was as simple as using a pH probe, and the total cost was in the same ballpark, I would likely have made a different decision.

So far, people that have the new SO2 probe are reporting positive results and are happy with it's cost/performance. As SO2 probe tech evolves I may join them ... time will tell.

 

[ibglowin]

While that looks like a good price through PI Wine they don't quote the shipping cost.

Anything over 100ml requires special handling by UPS driving up the cost. More Wine has 1L 25% Phosphoric for $65 including shipping. That works out to 100 SO2 test at $0.65 a pop just for the Phosphoric acid.

So the cheap A/O rig is not so cheap if you can't find a local source for Phosphoric Acid. Pros and Cons to both. The Vinemetrica uses chemicals that are currently only available through them. If they go under, what then. Its possible you could end up with a nice meter but no source of reagents. They do say they would give the "recipe" to another source who would then agree to make it up and sell but still. Just something to think about with either route.

 

[BobF]

While that looks like a good price through PI Wine they don't quote the shipping cost.

Anything over 100ml requires special handling by UPS driving up the cost. More Wine has 1L 25% Phosphoric for $65 including shipping. That works out to 100 SO2 test at $0.65 a pop just for the Phosphoric acid.

So the cheap A/O rig is not so cheap if you can't find a local source for Phosphoric Acid. Pros and Cons to both. The Vinemetrica uses chemicals that are currently only available through them. If they go under, what then. Its possible you could end up with a nice meter but no source of reagents. They do say they would give the "recipe" to another source who would then agree to make it up and sell but still. Just something to think about with either route.

In the other forum, people have discussed phosp acid sourcing ad nauseum. Everything from tile cleaner to having it shipped to local businesses to avoid the hefty shipping.

I had someone pick up the 75% for me. That's 300 tests for $13, or $0.043 per test.

Check out options you have for chemicals before you buy for sure and don't forget that you need NaOH and a small amount of HC1 as well!

 

[ibglowin]

The NaOH and HCL are relatively cheap and not considered hazardous to ship in the concentrations the A/O rig uses.

 

[Lurker]

I was in on the Vinmetrica group buy, best deal I ever made. I used the titrets before and 2 consecutive tests of the same wine were 20-40 ppm diff. Vinmetrica is most accurate.

 

[Runningwolf]

+1 what Lurker said

 

[BobF]

I was in on the Vinmetrica group buy, best deal I ever made. I used the titrets before and 2 consecutive tests of the same wine were 20-40 ppm diff. Vinmetrica is most accurate.

How long did the first probe last? How much are the solutions?

All things considered, what is the cost per test?

 

[Runningwolf]

Bob the I think the tests run about $0.50 each. This is the link to the products.

 

[Wade E]

I dont go to that other forum much if ever. Has anyone had to replace the probe yet?

 

[Runningwolf]

I believe one person had a defective one that was promptly replaced but I haven't heard of any others.

 

[Wade E]

Thats what I thought, just making sure.

 

[BobF]

I believe one person had a defective one that was promptly replaced but I haven't heard of any others.

My question isn't about defective units, but about normal useful life. You know, the same way pH probes have a limited life.

I'm *assuming* that the $.50/test is based on solution cost w/o including the cost of the equipment over it's expected life.

IIRC, the probe group buy was right at $200. If the probe last 12-18 months and costs $100. to replace, then the equipment cost becomes significant. $100 and 12-18 are made up numbers for illustrative purposes. The *real* numbers are obviously unknown.

I'm not knocking early adopters - I've been an early adopter many times in my life. It's just something I think should be considered when making a purchase decision like this.

 

[Runningwolf]

Bob I am not a chemist, just a wanna be. If it was not for the Vinmetrica I guarantee you I would not be testing for s02 now are for a long time. So after reading the first couple of reviews from reliable winemakers I jumped on it. Now I am understanding another part of the hobby and realize my wines were short on sulfite's. Of coarse if someone is just doing kits you can eliminate a lot of these tests.

 

[BobF]

Dan -

I agree testing is better than not testing. I'm simply explaining my rationale for going the A/O route instead of Vinmetrica.

The fact that you didn't consider A/O as viable is a good data point for potential buyers of SO2 testing gear, although knowing your pros/cons would be even more helpful.

 

[ibglowin]

The replacement electrodes for the Vinmetrica are online at their website and cost only $45. Thats not too bad and you may be able to find them cheaper online if you can tell what type of electrode they are using (via part number etc.)

If you take care of them and rinse and store them properly you should get years of trouble free service out of one.

 

[ibglowin]

From the Vinmetrica Website:

The SC-100 uses a polymer-bodied amperometric probe that resists breakage and should never need replacing.