Adding more sulphite

Michael, Since you only want it to last another half a year you have some flexibility. The effectiveness of sulfite is dependent on the amount of acid in the wine, if you don't have access to a calibrated pH meter it's hard to say whether you need any more or not. The real key is keeping oxygen away from your wine. 30 ppm is more than enough if the pH is 3.2, not enough if the pH is 3.4. A local schools science lab may be willing to test it for you.

If the wine is dry and a bit tart, you may be fine. Bottling it and keeping it cool will help protect it. If the pH is low and you end up with 60 ppm SO2 in it you may taste it so measurement of both the sulfite level and more importantly the pH would be preferable.

Joe

No, the guidlines for sulfite addition are not dependant on wine age; if you follow the standard charts based on pH you will be fine as long as you have a good closure. +/- 0.2 pH is not quite accurate enough; I would suggest you see if you can find a way to get to at least 0.1pH if possible or error with the uncertainty added; ie if you measure 3.4 pH assume it could be 3.6 pH and add the amount of sulfite needed for

That is what I meant, apolgies. You need a good closure and need to minimize contact with air (oxygen really).

At the moment,the glass container

I haven't seen glass airlocks either, plastic is fine as long as you trim off the excess sprue. Sometimes the mold lines are pretty prominent, just shave them off and you will be fine. I have had wines under plastic airlock for over 2 years with no issue.

Conventional wisdom is that about half of the first dose becomes "bound" (used up). But - having once reacted with all of the available "sites", subsequent additions will remain as all free SO2.

Campden tablets are based on the assumption that 50ppm free SO2 will provide "adequate but not excessive" sulfite in any wine that has a pH in the "typical" range of 3.2 to 3.6.

Thus, if I were unable to test my wine, I would assume that I only had about 15ppm free remaining after the first dose and that I should add about 30ppm to get it back up_near_that 50 ppm free (without exceeding that amount.) All of this of course based on the assumption that the wine has a typical pH.

Joe is right. It is always better if you can test things to better control outcomes, but in a pinch you can use the above procedure. HTH

Frederick

I like that advice, it's a good guide for those who don't feel the need to go out and get a lot of test equipment. Wine makes itself; the testing prevents drastic mistakes but can make some feel winemaking is just too technical. My background is testing so it's a good thing I'm married and have kids, otherwise I would have a gas chromatograph... :)

As to storing in the garage, I don't think those high temperatures will be good for the wine. If you could find a closet or space under a bed you might be better off. The higher the storage temperature the faster the wine matures. That can be good or bad. If you could find a way to keep it from getting above 75 F I think you might be better off. My wine cellar swings from high 40s to low 70's over the course of a year and as far as i am concerned that is just fine. I have some wines in there from 1998 still. For the most part mine is stored between 55 and 65 F.

"michael" wrote in message news: snipped-for-privacy@h25g2000hsf.googlegroups.com...

One final point.I am aware that it is good practise to keep wine cool- otherwise wine would not be traditionally stored in cellars.Also cellars will have a much more uniform temperature than other storage areas.My problem is that I do not have any storage space other than in my garage-not used to keep the car anymore,but full of gardening,wine and cidermaking equipment.I have thought of buying a cooler,but they are expensive,unsightly and apparently are not very satisfactory.I am going to rig up some curtaining to draw across the shelves,since the sunlight can shine in through the window directly on to the glass demijohns.However,I do not have any better ideas to keep temperature fluctuation low.At this time of the year the temperature fluctuates between 40F and 50F ( If we have a very cold snap,then I tend to put a heater on to bring the temperature up a little),but later in June- August,the temperature fluctuates between 60F and 80F.Does this really matter if one is trying to make good wine?I try to minimise the possibility of bungs coming out in hot weather,but apart from that why does my kind of temperature fluctuation harm the maturing wine? Best regards

michael

Jack Keller did a blog entry on how temperature effects the speed of the chemical reactions involved in the "ageing" process. IIRC it went something like this. Using a base line "cellar" temp of 55f, at "room temp" of ~72f the reactions occured about 8 times faster. And, at 90f they occured about 56 times faster. Unfortunately, this can't be used to speed up the ageing process because some of the UNdesireable reactions that can happen at the higher temps would happen so slowly at cellar temp as to effectively never happen at all. Bottom line: Cooler is better. Memory ain't what it used to be. Those interested might want to look up that blog entry and read it for themselves.

If you are stuck with using the garage, I might suggest putting white shades or drapes on the windows themselves to prevent the sun getting into the garage and heating things up. At least it shouldn't get much hotter that the outside air temp that way. HTH

Frederick

That doesn't sound right - 28 times faster for 10C difference?! I'm pretty sure one of my reference books says it's 2x faster for chemical reactions for each 10C temperature increase. If it was 28x, wouldn't that mean that 1 year of aging at 55F would be "chemically equivalent" to 28 years of aging at 72F? I've got white wines at both those temps, and they don't taste much different after 1-2 years.

Pp

Here is the link:

But he must be working on it because the last entry showing right now is for Feb. 2006. I will try to find the date of the entry when the page gets restored to normal. Sorry..........

Frederick

OK. Here is the new link:

Look at the blog entry for December 5th, 2007. Titled "Temperature and Wine". HTH

Frederick