In a glass of cider

It seemed I was a mite of sediment
That waited for the bottom to ferment
So I could catch a bubble in ascent

I rode up on one till the bubble burst
And when that left me to sink back reversed
I was no worse off than I was at first

I´d catch another bubble if I waited
The thing was to get, now and then, elated

These words I found at a white-board at my work some years ago