BruStop works very well. I can leave that second cup of coffee in there for a long and it tastes just like the first cup.
I would have given 5 stars but the Ovrlndr doesn't keep the coffee as hot or warm as a normal thermos would. Need to reheat the second cup if you don't hurry up with the first.
I have 2 of these because of the BruStop and just recently ordered the Base Camp 48 oz version from Planetary Design, it also has BruStop.