We were a bit surprised with our pre-bottling panel to find that there were “No detectable sulfites”
I’m attributing that to the two rounds of Bentonite fining, and was surprised that what I took to be an essentially physical process of agglomerating long chain protein molecules to the high surface area particles also had a significant chemical aspect of reacting out the Sulfite.
I’m assuming you do not have the ability to check your own Free SO2’s? How do you add? Do you use those crappy tablets or granules? If so, I’m not surprized you have no SO2 left. Those things suck. You really need a way to check your own SO2’s.
I’ve found the tablets sitting undissolved at the bottom of a tank, but I was told that this problem has been fixed. I have had more faith in the Efferbactol. Why do you not like these products?
Because they suck. ![[wow.gif]](/uploads/db3686/original/2X/7/7d450e9830889c8943b674446a21b7254cad657e.gif "wow"){kind=small}
Seriously, even when they DO dissolve, they never seem to add as much as you think (even taking int account the natural tendency for only getting a very much smaller add than what you intend). Plus they are very expensive relative to just making your own solution. For a winery our size, they just aren’t practical.
But bottom line, no matter what you use, you should always have a way to check your own SO2’s, or short of that, have them checked frequently. My point to Sheldon being that they may have been WAY lower than he expected, bentonite not withstanding (whose impact would be minimal at best).
Winner, winner chicken dinner.
we use Vinquiry at present, did not have believable results with “test kits”.
I know we need to buy suitable lab tools, its one of many items on the when time/money permits. (winery is being funded on available cash flow…)
Have been adding powered Metabisulfite based on pH to a target range, with quarterly samples to vinquiry.
I agree with Linda. Testing yourself is key. We do not find that Bentonite affects S02 significantly. Handling wine does, so stirring, racking etc. do cause some loss, but the loss should not be dramatic.
Until recently, we have used AO and ripper. I was not happy with what seemed to be inconsistent results with our AO, which is sink driven. We recently bought one of these:
on Steve Gower’s suggestion. I have not yet completed my testing, but it is easy to use and so far it looks pretty good in terms of accuracy. Except for the syringe part. Once we finish bottling our whites, I will complete testing and post my results.
I hope it works out for you, Andrew. I sure like mine. I tried the syringe only once then bought a $30 burette just like you would use on an acid titration setup or even use the same one. In fact I mounted the probe and burette to my acid titration stand and use the stir plate from that setup as well. Then all you have to do is slowly add solution and wait for the beep.
http://morewinepro.com/view_product/6990//Automatic_Free_Total_SO2_Titrator_Hanna%23_HI_84100
$650. It paid for itself in lab fees in 6 months. If you’re running wine down to zero free SO2 it will pay for itself even sooner in ruined wine saved.
How you add is as important, or more important than the amount you add. A 100ppm tablet sitting at the bottom of a barrel is going to give you a whole lot less free SO2 in your wine than 30 ppm properly mixed into the wine. If you can do it while racking, that’s best. Normally I add at the midway point, allowing the SO2 solution to be mixed by the remainder of the wine being added.
For wines not being racked often I followed some advice that I picked up from Brian and Adam talking a few years ago and do a larger initial dose with smaller interval adds as needed. At topping is best, when you can add the solution, stir and then top without making a mess.
Here’s another gotcha that I’m sure will zap you if it hasn’t already. Your topping wine needs to get regular SO2 treatments as well.
I’ve been using the efferbaktol exclusively for three years now. I find it very easy to hit SO2 targets, perhaps because I’m used to them. While the excess cost sucks, I save a ton on stirring and stink. I used to hate working with the solution and don’t want to make any one else do it. Just as a counterpoint to Linda’s experience. Having your own free sulfur setup is money well spent.
Paul,
I have heard mixed reviews of those. You like it? I know some do.
What is your total time, including setup to run a batch of 10 tests?
Any issues with set-up or maintenance?
Have you compared your results to outside testing?
Thanks!
Besides just convenience, the thing I like about efferbactol when you are adding to barrels is that it immediately spreads over any surface space, giving you a nice concentrated dose at the wine/air interface where the acetobacter lurk. I suppose the flip side is the question whether it gets down to the bottom of the barrel very effectively to deal with any brett lurking there.
Andrew, Stef and I love it, but I would give some thought to your process and scale before deciding on it. We bought this after talking with Dan and Therese Martin, who work just about the same way we do (two people, doing almost all the work on their own in a small space.)
We’ve never run 10 tests in a row, and I don’t think we ever would. Our usual process is Stef preps the tester while I hook up the pump. It takes about 15 minutes. We never handle more than 3-4 lots at a time, so the most testing we ever do is 4-5 in a day. It takes her about 20 minutes per test. For us that works fine. She’s testing while I’m moving barrels, or rinsing or doing some other task. If your process is to draw 10 samples and go do testing, I think this is the wrong tool, it would take too long.
The net for us is it ads no additional time to use this tool. We can rack out 10-15 barrels in 3-4 hours and do one lot at a time. The testing is running ‘in the background’ while we handle everything else.
I do still run SO2 when I send in samples to verify our work and it’s never been more than +/- 10% (4-5 PPM). When we first got it we also did a ton of testing with it of before and after samples to see what the effective Free SO2 was for every ppm we were adding. Basically I was having Stef test before I added SO2 and then after and compare the results. I was doing trials adding in 10 PPM doses and in larger doses to see what was most effective. What I was really trying to test was how much Free SO2 and total SO2 was lost in the addition process so I could adjust my additions to account for that. I found it very accurate through those trials with no really unexpected results.
Hi Paul,
Thanks for your detailed reply.
Sounds like it fits your situation better than it might fit mine.
We’ll see if the Vinmetrica works well enough for us or not.
Sheldon, are you dissolving the KMBS in some water? It appears that you are adding the powder only.
We have been simply adding kmbs as a dry powder, stirring gently to dissolve.
Bought a Hanna inst 84100 (best price Amazon)
After calibrating pump, all samples are at “400 ppm”. (including some Beringer )
Electrode reading at 190 mV pre and 347 mV post titration
Now awaiting replacement unit.
I use a cheap and cheerful titration method for free SO2. It is accurate to about 5ppm which is good enough to know you are on the low side. It can;t measure total SO2 but I have found that if you add up all your SO2 additions after fermentation you get a pretty reliable value for total.
The redox state of the wine is most important. If the wine is in an oxidative state, it will gobble up SO2. If it is in a normal state, a good rule of thumb is that you need to add 1.5 times the amount of free SO2 you are missing. So for example. If the wine has 10ppm free and you want it to have 20ppm, you need to add 15ppm as KMS or other form.
My guess is that the loss of SO2 is due to racking during Bentonite fining. If the process is not carried out in the total absence of oxygen, you are going to lose free SO2 as it scavanges the O2. Make sure the tanks and pipes are full of CO2 or other inert gas and add CO2 to the tank or barrel you are emptying as you go to stop it sucking in oxygen.