What would be Liquidol's shelf life in an unopened bottle?

Will be getting back with printing soon after four years. Just waiting on a few more pieces of materials by mail. I found what appears to be an unopened bottle of Liquidol paper developer, in a liter bottle. I slowly opened the cap and heard a very faint wisp of air. The few droplets of solution under the cap had a slight pinkish tone to them. When I drew a small portion out with a pipette the solution looked clear. I am taking it that this developer may still be good? I tightened that cap right back up! The condition of the bottle is somewhat sucked in.

it was famous for being long lived. since it is a paper developer it would be low risk to try it. if it is no good, Just mix up something else. dreamed by by the late "Photo engineer"

If it's clear, it's probably fine. Working solution yellows when it oxidizes, so that's probably true of the concentrate as well. Enjoy printing!

I'm not sure that Liquidol's shelf storage life longevity is what it was well known for - I believe it was designed with a goal of the working solution having a long life when in the tray or between sessions if stored.
But that may be consistent with good shelf storage longevity.

What About Bob said:

When I drew a small portion out with a pipette the solution looked clear.

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Sounds good to go.
If it had died, it would have gone black.

Thanks everyone.

This was the second bottle that was bought. I think it was in November or December of 2019. So four years ago. Wow, that is awesome staying power!

I suspect that any developer concentrate still sealed in its original packaging would last a very long time; it's the oxygen that causes the developer to go bad.
I hope yours is still good- best of luck- and report back with your results, please!

Test it before you use it or discard it. Then if it works, use it. I test all my developers before each batch of film as part of my procedure.