# My Aeration-Oxidation Free SO2 Setup



## ibglowin

Just finished setting up one of these and thought I would post some notes.




Pretty simple, easy setup. Parts can be obtained from a variety of sources including eBay, Amazon etc. Its the chemicals (and their cost) that can be a big drawback over the simple (Accuvin) test kits. Since I am a chemist by trade, its not so much a problem for me. Biggest expense is finding 25% solution of Phosphoric acid. Since it is a hazardous solution, UPS charges a premium for delivery. These chemicals also have a limited shelf life and should be refrigerated between uses. Order/makeup only what you think you will use up in a 6 mo time frame.





Accuvin test kits are fine for probably 90% of the home hobbyist.

This test takes 5 minutes to setup, 15 minutes to run each sample and then 10 minutes to clean up and put away.

My particular problem is that I have limited color definition and all my Accuvin test seemed like they turned out all the same color (to my eyes)

Very hard to discern the correct color in any kind of light. This test provides an easy (huge) color change that even my eyes can see quickly. The endpoint can be detected within a drop or two. Not much room for error in endpoint detection. Again good for my eyes!

The burette and mag stirrer are not a necessity, again chemist by trade. Most people can get by with a 10ml plastic syringe and just swirling each addition. The mag stirrer does get it into solution in a split second so you can see the approaching endpoint much faster. Much less chance of overshooting the endpoint.

20ml sample of wine is required





When the Phosphoric acid is added to the wine any SO2 is reacted with and liberated from solution. The SO2 gas is flushed from the sample vessel over and trapped into the reaction vessel. The reaction vessel has 10ml 3% Hydrogen Peroxide (same as the grocery store kind), 6 drops of SO2 indicator solution (found online) and 40ml distilled H2O.





The (now acidic) Sample is titrated back using 0.01N NaOH solution. (found online). Drops are added and stirred until the solution turns from the vivid pink to a grey color. End point is then right at the change from grey to green.







The Free SO2 is calculated by taking the amount of NaOH required and multiplying times 16.

In this instance I used (3.0ml NaOH) X 16 = 48ppm Free SO2

All in all I find this a very accurate (and fun) test to run. In the 3 test I have run to date I am finding that my wine is pretty close to perfect just before bottling using the normal addition of 1/4 tsp K-Meta every 3 months. I have been able to cut back from a full dose just before bottling to a much more controlled addition based on the pH level of the wine as well as an accurate assessment of the free SO2 in the wine.


----------



## Randoneur

Nice well presented instruction for those of us looking to get more accurate measurements. Does't look much harder than most other tests.


----------



## Runningwolf

Very cool Mike and I like how you never stage the backgrounds in your pictures (monitor LOL). Thanks for sharing.


----------



## ibglowin

Had to get rid of the swimsuit model just for that shot!


----------



## grapeman

What kind of pump is that Mike? I assume it pumps air but is it vacuum or compressor like an aquarium pump?


----------



## ibglowin

$10 Aquarium pump. It does have a small valve to regulate the air flow.


----------



## AlFulchino

thanks for sharing Mike..i wish you were readily nearby for things like this!


----------



## Randoneur

Mike, 
Did you usepipettes instead of fine point burettes to induce the air?
I assume the opening size on the trapped SO2 flask is important for good acidification.


----------



## ibglowin

One of my sparging tubes broke while trying to get it inserted. 

I found that a 2ml disposable pipette was pretty much a dead match so I scored it at the right length and popped it in half. Works perfect. I used a little silicon grease to get them inserted through the #5 Stoppers.


----------



## robie

This sure makes it easier for testing red wines.


----------



## SBWs

I have tried this set up and found it works very well. I did find that the NaOH solution is very important it must be .01N and also the amount of the wine sample is another thing that has a direct effect on the out come. Multiplying by 16 only works if the wine sample is 20ml. Maybe George can start selling some of this stuff.


----------



## Randoneur

Full formula which accounts for molearity and sample size (from WineMaker Magazine):
*SO2 (ppm) = (mL NaOH * N NaOh * 32 *1000)/ mL sample size*
 
example: 
SO2 (48 ppm)= (3 mL NaOH * 0.01 N NaOH * 32 * 1000) / 20 mL sample size
 
Stick to using 0.01 NaOH and 20 mL sample and its just the 3mL NaOH added x 16.


----------



## ibglowin

Good point! I left that little detail out in my calculation.

0.01N is dilute enough in that you can easily measure out enough and not go past the end point in a single drop. It will take you up nice and easy as long as you are dropping one or two drops at a time.


----------



## SBWs

I was reading on another board that citric acid could be used in place of Phosphoric acid, and also if you use a 32ml sample you multiply by 10 (easier to do math in head) So I made up a solution with 1 gram of K-meta to 1 gallon of water which according to Jack Keller 's site should be 150 ppm SO2. I then added 16 ml and 16 ml of distilled water to the flask for a 75 ppm sample. Then added 6 grams of citric acid and ran the test and came out with 60 ppm. Wasn't off by much. Didn't have anymore phosphoric acid to run another test to see what that came out to. The K-meta is 6 months old and my gram scale isn't the best. I'm thinking the citric acid might work and be a lot easier to get hold of. Wondering if anyone else has ever tried other acids.


----------



## ibglowin

I read that tile and grout cleaners (at least some so make sure and read the label) available from all hardware stores contain 25% phosphoric acid. I have not had a chance to check it out yet.


----------



## Randoneur

I'm getting ready to buy more Phos acid. Just wondering if you've found somethingto use in order to avoid the HAZ shipping cost?? 


Did the tile and grout cleaner work? If not I'm going to have to findone the lab supply houses here that will sell to me.


I looked a Hydroponic "acid down", but it looks like it has small amounts of other acids added to the phos.


----------



## ibglowin

I haven't really looked. I have access to Con Phosphoric that I just dilute down.


----------



## wine_wizard

So I have tried the "blue box store" tile and grout cleaner... as the phosphoric acid.

a) using test tubes ( not the flasks ) i had an issue with "foaming" (bubbles) filling the wine/acid tube and going up into the hose going to the "indicator" tube.

b) suspect that there are additives to the cleaner that in fact may encourage that ( and that chem lab phosphoric acid would not have those )

( btw, another trip to the aquarium dept, got me a "manifold" for aeration stones that allowed me to regulate the air flow volume nicely from my pump )

c) the directions i used said to go for 15 min and then titrate back to original color which i did, but out of curiosity i let the aeration continue, and after another 5 minutes needed another drop or 2 to maintain color.
This continued for an hour ( at 5 - 10 min points ) at which time I ended.

suspect (1) the acid is weaker then the 28% and (2) that the "bubbles" delay the release of the so2 into the indicator container... between the start (15) and end 60 min i had a 3 to 1 ratio of "measured" so2 ...


----------



## doughowe

lindseyd said:


> So I have tried the "blue box store" tile and grout cleaner... as the phosphoric acid.
> 
> a) using test tubes ( not the flasks ) i had an issue with "foaming" (bubbles) filling the wine/acid tube and going up into the hose going to the "indicator" tube.
> 
> b) suspect that there are additives to the cleaner that in fact may encourage that ( and that chem lab phosphoric acid would not have those )
> 
> ( btw, another trip to the aquarium dept, got me a "manifold" for aeration stones that allowed me to regulate the air flow volume nicely from my pump )
> 
> c) the directions i used said to go for 15 min and then titrate back to original color which i did, but out of curiosity i let the aeration continue, and after another 5 minutes needed another drop or 2 to maintain color.
> This continued for an hour ( at 5 - 10 min points ) at which time I ended.
> 
> suspect (1) the acid is weaker then the 28% and (2) that the "bubbles" delay the release of the so2 into the indicator container... between the start (15) and end 60 min i had a 3 to 1 ratio of "measured" so2 ...



Hi All. I just finished testing using sulfamic acid in place of phosphoric in my AO tests. I got sulfamic acid as a powder in the tile section at Home Depot. So far a 1% w/v solution used in place of the 25% phosphoric acid seemed to work fine, and no foaming or other issues from additives in other tile cleaner products. That comes down to something like a quarter teaspoon per 10ml H2O to make the acid solution. For 6 or 7 bucks I got enough phosphoric acid for hundreds of tests, and it should be pretty stable in the dry form so it won't go bad. Might even be able to use less...didn't try that yet. The only caveats is I haven't tested it with wine yet...only with sulfite standards made up in water. Wine has buffers so there is a small chance it won't work the same with wine..might take more..not sure..but it looks promising. Thought I would share in case someone else wants to give it a whirl. Very economical compared to phosphoric...
Doug


----------



## doughowe

doughowe said:


> Hi All. I just finished testing using sulfamic acid in place of phosphoric in my AO tests. I got sulfamic acid as a powder in the tile section at Home Depot. So far a 1% w/v solution used in place of the 25% phosphoric acid seemed to work fine, and no foaming or other issues from additives in other tile cleaner products. That comes down to something like a quarter teaspoon per 10ml H2O to make the acid solution. For 6 or 7 bucks I got enough sulfamic acid for hundreds of tests, and it should be pretty stable in the dry form so it won't go bad. Might even be able to use less...didn't try that yet. The only caveat is I haven't tested it with wine yet...only with sulfite standards made up in water. Wine has buffers so there is a small chance it won't work the same with wine..might take more..not sure..but it looks promising. Thought I would share in case someone else wants to give it a whirl. Very economical compared to phosphoric...
> Doug



Hi,
Thought I would report final results I've had with sulfamic acid in place of 25% phosphoric. I noticed that the rate of color change in the peroxide solution was a bit slower than what I was used to when using phosphoric acid. So, I've upped it to 2% w/v sulfamic acid and it works great! No foaming problems and you can adjust the acid concentration higher even if you think it is necessary for your wine. The wines I tested tonight all worked great with the 2% sulfamic acid and 15 minutes of aeration. I recommend it. Good luck and keep testing...it's the right thing to do!
Doug


----------



## ibglowin

Interesting results and good to know there is an alternative reactant out there.


----------



## Norske

ibglowin said:


> I haven't really looked. I have access to Con Phosphoric that I just dilute down.



Can you share more in detail how you do this?


----------



## ibglowin

A bottle of laboratory grade phosphoric acid is 85%. You only need 25% so ~30ml in 100ml gives you 100ml of 25% solution.


----------



## chrisjw

doughowe said:


> Hi,
> Thought I would report final results I've had with sulfamic acid in place of 25% phosphoric. I noticed that the rate of color change in the peroxide solution was a bit slower than what I was used to when using phosphoric acid. So, I've upped it to 2% w/v sulfamic acid and it works great! No foaming problems and you can adjust the acid concentration higher even if you think it is necessary for your wine. The wines I tested tonight all worked great with the 2% sulfamic acid and 15 minutes of aeration. I recommend it. Good luck and keep testing...it's the right thing to do!
> Doug



Thanks for the suggestion. Sounds like a great alternative and timely as I am running out of phosphoric acid.

Just wondering if you tested your wine with the 2% sulfamic acid as well as the 25% phosphoric acid over the 15 minutes and got the same result?


----------



## doughowe

chrisjw said:


> Thanks for the suggestion. Sounds like a great alternative and timely as I am running out of phosphoric acid.
> 
> Just wondering if you tested your wine with the 2% sulfamic acid as well as the 25% phosphoric acid over the 15 minutes and got the same result?



Hi Chrisjw,
I didn't do the test the way you describe it, though it would be a good one to do at some point. I'm out of phosphoric currently. I had a wine sample I was testing though, and it was reading out at 8ppm, which was low. To do a positive control for the 2% sulfamic I repeated the test with 50ppm sulfite from KMBS spiked into the wine sample. The result was 62ppm...so it seemed to liberate all the sulfite I spiked into my wine sample. Based on that I was convinced it was working properly. I've tested several other wines with the 2% sulfamic and got expected/unsurprising results. Seems to work.
Doug


----------



## SBWs

Awhile back I was experimenting with using a solution of 10 grams of citric acid and 10 ml of distilled water. It seemed to work, but then I got a bunch of phosphoric acid and never finished the experiment.


----------



## chrisjw

I finally got around to trying out the sulfamic acid. The 2% (w/v) solution (2 grams in 100 ml of distilled water) worked great. It produced the same results as the phosphoric acid when aerating for 15 minutes, although a shorter duration, which I did not test, might be sufficient. Also just an FYI, I weighed 1/2 tsp of the crystals and it was 3.07 grams. Since only 10 ml of the sulfamic solution is used in a test, the amount of sulfamic acid crystals required for a single test is too small to measure by volume. Best to make more and store it. 

Anyone have any idea how long one could store a 2% solution of sulfamic acid? I could not find any information on the shelf life of the product although I found the shelf life of a similar product to be 1 year. Any concerns here?


----------



## seth8530

Very cool thread, nothing like a little bit of science to make my evening.


----------



## ibglowin

Thanks for posting your results. This sounds like a cheaper alternative than phosphor acid. Making 250-500ml solution is definitely the way to go. 

Normally prepared chemical solutions are good for a minimum of 6 months. 

They should last at least 12 months if you keep then in a refrigerator.



chrisjw said:


> Anyone have any idea how long one could store a 2% solution of sulfamic acid? I could not find any information on the shelf life of the product although I found the shelf life of a similar product to be 1 year. Any concerns here?


----------



## doughowe

I believe sulfamic acid can hydrolyze in aqueous solutions to ammonium bisulfate. I don't know the rate at which that may occur. The ammonium bisulfate may still be acidic enough for our purposes that this change wouldn't really matter. The sulfamic acid solid is stable. I weight out 1 gram and dissolve fresh in 50 ml for each day of testing, but I would be interested to know if anyone stores a solution and starts to suspect problems over time.


----------



## sour_grapes

I would love to try this. Unfortunately, the pictures in the original post seem to be missing for me. Is is just me, i.e., can others see the photos? Mike, if they are missing, would you consider reposting them?

Thanks,
Paul


----------



## ibglowin

I edited the URl and now they are showing up for me. Not sure what happened. Let me know if you still are not seeing them. Make sure to clear any cached web pages.


----------



## cool77

hmm, I've just tried 3 computers and pics does not show up anymore. Then tried my cell and it worked. One computer had never been on this forum. So cache is not the issue... Weird.


----------



## sour_grapes

Well, no joy so far.

First I tried 4 different browsers. No help.

Next, I viewed the html source of this post, so I could see the URL of your pictures. One was, for example, http://cdn.winemakingtalk.com/forum/images/uploads/temp/20100921_101504_DSC02744.jp However, when I tried to access that location, I got a message that the object wasn't found at the supposed position.


----------



## ibglowin

Other forum members have reported their attachments not showing up as well. I sent a PM to the site owner yesterday to have him check out whats going on.


----------



## ibglowin

The direct link to the images works. So not sure why they won't display in the post properly.

Try them:

http://www.winemakingtalk.com/images/uploads/temp/20100921_100913_DSC02743.jpg

http://www.winemakingtalk.com/images/uploads/temp/20100921_101504_DSC02744.jpg

http://www.winemakingtalk.com/images/uploads/temp/20100921_101819_DSC02742.jpg

http://www.winemakingtalk.com/images/uploads/temp/20100921_102514_DSC02741.jpg

http://www.winemakingtalk.com/images/uploads/temp/20100921_103119_DSC02747.jpg


----------



## sour_grapes

Mike,

Thanks, those links worked fine. I am quite interested in setting up such a rig. To date, I have not been testing for SO2 levels, and this seems like a good way to go.

Thanks,


----------



## ibglowin

Morewine sells this as a kit for a little over $100 with enough reagents to do like 5 test. They also have very nice youtube videos that show setup, how to "zero" your SO2 titration vessel and how to tell the endpoint. For the money you can't beat this thing as its very accurate and still the defacto standard in the wine industry. It does have a small learning curve and at first takes a bit of time to setup and then cleanup but after you get some experience you get more much efficient for sure.


----------



## chrisjw

doughowe said:


> I believe sulfamic acid can hydrolyze in aqueous solutions to ammonium bisulfate. I don't know the rate at which that may occur. The ammonium bisulfate may still be acidic enough for our purposes that this change wouldn't really matter. The sulfamic acid solid is stable. I weight out 1 gram and dissolve fresh in 50 ml for each day of testing, but I would be interested to know if anyone stores a solution and starts to suspect problems over time.



I asked the manufacturer about the shelf life and this was their response:

Good day,

Thank you for contacting us.

There is no shelf life on the acid cleaner. If the sulfamic crystals have been properly stored in the original container, and as long as the crystals have not had contact with water/moisture this would be a good workable product.


----------



## chrisjw

Is there a way to quickly and easily test the strength of a sulfamic acid solution (over time) to determine shelf life (as it pertains to releasing Free SO2 in wine)?


----------



## chitownwine

Thanks for the helpful info. I have recently purchased a similar setup from midwest with enough reagants for 20 or so tests. At this point I am predominately making kits are you kit makers who are checking sulfite levels correcting sulfite based on a measured ph or just shooting for a level prior to bottli g, say 50 ppm. Since I know kits are balanced can we assume the ph is a certain level or do I need to really invest in a ph meter even with kits.

Thanks for the help.


----------



## ibglowin

No, you will need a pH meter as the amount of SO2 required to protect a wine is directly proportional to the pH value of the wine. Lower pH needs less, higher pH needs more.


----------



## chitownwine

Thanks. Any recommendations on a decent but resonable ph meter. Figuring the dip sticks aren't worth trying even. Also I see calculators such as the winemakers mag one, you need to input the mg per liter of desired molecular so2. Do you using use 0.8 for whites and less like 0.6 mg/l for reds. Sorry for all the questions, but much appreciated.


----------



## ibglowin

No problems thats what were here for. I use the pHep 5 and love it. Others really like the Milwaukee 101 model for about the same price. The winemaker mag calculator is what I use. I dose everything at the 0.8 level. Once you input the pH of the wine, if you look down (just below the input area) it will tell you what level of SO2 (in ppm) is required to protect the wine. Then you enter that level into the input area, your volume and starting level of SO2 (if known, zero if none has been added yet) and it will calculate the addition to make. If your doing a kit add the pack that comes with it. Remember that the first time you add SO2 about 50% will get bound up in the wine, thats why you add so much up front. After that you are good for bulk aging for quite a while if you are aging in a carboy. Much less if you are aging in a barrel as they let lots of O2 in slowly.


----------



## chitownwine

Thanks mike that phep5 seems like great choice, will probably end up ordering that one. Btw great website you made, that has been on my long list of things to do for a while now.


----------



## ibglowin

Needs updating!


----------



## chitownwine

You still making predominately the cellar craft showcase kits? I have my first double batch showcase zin in a vadai right now which is tasting amazing. If so you source the kits locally? I've been having a hard time finding a good retailer that doesn't try to charge ridiculous prices.


----------



## ibglowin

I have moved on now to mostly fresh grapes. I still make all white wines from kits. I always get 16L or 18L kits and they turn out very good.


----------



## cool77

Hello, 

I'm considering buying the aeration test from morewine. I think buying from many suppliers will cost more. But once I would need to replace reagents I would like to buy locally when I can. 

Here is what I have in minds :

Peroxyde : buying from drugstore like suggested

0.01N HCL : I'm looking where I can buy it and make my own. I did not find any up to now.

0.01N Naoh : I found this from a local store : "Sodium Hydroxide also called NaOH, Caustic Soda or Lye. Sodium Hydroxide resembles *Potassium Hydroxide* in its chemical properties and has similar uses. Ingredient Depot's Sodium Hydroxide (NaOH / Caustic Soda / Lye) is in micropearls form (25 mesh size or 3/4 millimeter) and is of Anhydrous and Technical Grade. Sodium Hydroxide is hygroscopic in nature readily absorbing water and carbon dioxide from the air. Sodium Hydroxide (NaOH / Caustic Soda / Lye) mixes easily with water, alcohol, and glycerol. Sodium Hydroxide is exothermic generating heat while dissolving." Is it ok to make my own?

25% solution of Phosphoric acid : Like suggested 2% w/v solution from sulfamic acid. Hardware store has it.

SO2 indicator : I'll buy online.

Any comments?

Thanks,

Yves


----------



## ibglowin

If you can get the HCL and the NaOH shipped across the border Morewine is plenty cheap on the this as a reorder stocked item. It is only the Phosphoric acid that is costly.


----------



## cool77

Thanks! I guess it's ok for shipment I got a shipping quote.

Is there any disadvantage doing the 0.01N HCL and 0.01N Naoh solutions? Accurancy might be an issue... I have a 30g +/- 0.001g scale but the volume measurement is another story.

The only source I found for HCL is muriatic acid, don't know if It's ok.

Well I think I'm 14 years old again. lol I had fun doing lab tests.

Yves


----------



## ibglowin

I would trust the stuff being sold by morewine any day of the week. The HCL is not used for anything other than getting your sample ready to titrate. You add a drop or two to get it closer to the endpoint before the start of the titration. Its the NaOH that is critical. This is made from very high purity stock con HCL which is standardized before they bottle into smaller bottles for shipment.


----------

