I have a bottle of Littlemill with a double measure taken from it (c 5cl). How long would I have to leave the bottle before the flavour disappears? Would it disappear quicker if I give the bottle a good shake every now and then?
So then, I take it you don't like the flavour of Littlemill?
Interesting question....unfortunately, deliberately trying to make a malt lose its flavour is not something I specialise in!

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However, I had a 700 ml bottle of Glenmorange Port Wood Finish that had about 175-200ml left in the bottle. I consumed the first 500ml over a 12 month period, and then when I moved house, the bottle was put in a box and forgotten about for nearly three years. When I recently re-discovered the Glenmorangie, I tried a dram, and it had almost completely lost its flavour.
I also once tried the last 50ml of a Bottle of 1958 Highland Park that had been bottled in the mid-1960's, had most of the contents consumed over a two year period, and then left to sit for over 35 years. It had lost all its
original flavour, but had also gained
other flavours. Sadly, none of these new flavours were pleasant. In truth, I almost threw up!
So what do we conclude? If a bottle of Glenmorangie with 500ml removed takes just under four years to almost lose its flavour, how much longer will a bottle of Littlemill with 50ml removed take?
We can only guess, but I'd place my bid at, say, 10 to 12 years. I'm not sure whether shaking it would accelerate the process. Excluding the comical element of your question, why do you ask?
Cheers,
Admiral