My paper is almost 3 years old and works fine. The Beverage People in Santa Rosa are unaware of a shelf life limit as long as the paper is stored properly average temperature and in the dark.

Jon thanks so much for getting back to me. The side-by-side test sounds pretty convincing!

Robert The paper in my original kit lasted 10 years and I never saw a problem. I got good results from every sheet. My recommendation is "don't toss it". GB

My supply got to about 2 years old before I ran out and there was not sign of failure to react. I suspect that the paper is special only in that it has a controlled ph. and is free of odd contaminants. The wicking effect of the paper drawing up the orange solution seems more related to the high purity linen rag content of the paper and its ph that to anything else. Why don't you give a sheet a bench trial using Some wine samples whose malolactic population you know.via other means? .

Hey Robert if you kept the paper dry (I keep mine in the big white airtight plastic jar it came in) it lasts indefinitely.

Hello the paper has a long shelf life may be up to 20 years as long as it is kept dry. It is the chemicals that go bad. The mobile phase as it is called can go bad somewhere between two to three years of life depends on what two manufacture does you might have to use an actual test standard to determine that I have not had my test kit for that long however I did it is a year old and it is still working properly I have not had any problems at this time. I hope that helps feel free to ask me any more questions

Mine is probably 3+ years old I keep it pretty well sealed up and I keep using it and haven't seen any issues.

I have some paper that is many years old -- more than 5 years. I only use two-three sheets per year I have it stored it at room temperature 68-74 degrees. The paper still works. I intend to keep using the paper until it doesn't appear to give reliable results or until it runs out.

Good question. I had a similar situation with some 4 year old paper. Since the 4 year old paper was almost gone I ran side by side tests with old and new. I thought the results were basically the same between the papers. I always store my paper in a dry dark room inside the house and in a double zip lock - for what it’s worth. The paper is too darn expensive.

As long as you keep it in a dark place it will last a long time. I used some that was 10 years old with good results.

The paper lasts a very long time. Many years. However the solvent does have a limited life. As it goes bad you will see the spots become less and less well defined on the chromatograph.