I've recently started using Soylent 2.0 Original. I find that as it gets warmer, it's harder to drink. I've tried protein shakes before in the past so getting accustomed to Soylent has been slightly better but as it gets warmer, to me it gets "thicker" (may be just in my head) and tastes more "vitamin-y" if that makes sense.
I'm on day 2 of getting into it. I'm hoping/have plans to move to a 90%-100% diet soon.
I was wondering the same thing on how to keep it cold. The first day I tried to drink it, it took me over an hour to drink 3/4 of the bottle and by that time I was "forcing" myself to try and finish it while warm. Today, I stuck a bottle in the freezer for a little bit until it had a Wendy's Frosty like texture and was able to drink a full bottle in roughly 30 minutes.
I would think that the freezable can koozie things would work pretty good at keeping it cold, but when the koozies get warm you'd have to replace it with something else.
I'll also look into the options that others posted above.