Potassium at Pressing?

(Lum or others here can give you more precise answers) As best I understand and can explain;

Ripper is a method for determining free SO2 using iodine as an oxidizing agent. Essentially it involves a couple of titrations watching for color shifts. It works OK for white wine (although I never got the same result twice!) but is damned near useless for red wine - can't recoognize the color shift (at least, I can't). It also requires a lot of prep work - creating and normalizing the solutions. Too much work, too inconsistent, and useless for red wine. For me, wasn;t working.

Aeration-oxidation is a method of releasing SO2 from the wine being measured by acidifying (is that a word? acidulating?) it then pulling air through it in a closed system, passing that air through a second medium (hydrogen peroxide) which accumulates the released SO2, then titrating that H2O2 solution to determine the actual amount of SO2 it has accumulated. It can be used to determine both free SO2 and total SO2. Sounds complicated but is acutally pretty easy - and the 'color shift' on the titration is easy to spot. I get consistent results which I believe to be accurate.

AO kits are available for sale (see any of the major winemaking retailers online) - but are spendy becuase they use a vacuum pump to pull the air through the system. Being a cheap SOB I bought the basic components (titration stand, clamps, beakers, hoses, etc) and then bought a little aquarium pump; I push air through (pressure aspiration) rather than pull it through (vacuum aspiration). Saves a heap of $. An aquarium pump is relatively cheap compared to a vacuum pump. A winemaking friend / mentor (a commercial winemaker) showed me how to set it up as such and pointed out the only possible flaw; the system has to be airtight lest you lose any of the released SO2 (whereas in a vacuum aspiration system you may pull extra air in but won;t lose any SO2). So I make sure the hoses and clamps are secure and it's good as gold.

It also satisfies the basic Frankensteinian impulse to have lots of cool looking lab apparatus, complete with colored fluids bubbling away. ;-)

As for titrtets I tried them back a couple years ago; couldn't get consistent results, and frankly mistrusted the results I was getting. Someone else can better explain how they work.

Titrets are Ripper test, with the iodine solution sealed in the ampule. You draw the wine in and watch the colour change.

Pp

A 90-gallon batch??? I like your style.

Yeah. Year 1  gal zin; year 2 60 gal cab + 20 gal 2nd press wine; year 3 90 gal cab + 15 gal 2nd press, + 5 gal port. We like scale-up. We make enough to drink for the whole year (me and a friend). We'd like to get enough stock to be able to drink last year's wine. Each of us is on a 40 gal consumption pace (including give-aways and family,etc).

Marco

Lum Eisenman wrote: