How to keep perpetum or infint cold?

I'm going to be giving some if the insulated bottles a shot, however, I haven't had any issues with Infinit when it has gotten warm--besides the fact that it tastes warm. I was pretty surprised how well it stayed.  I've been using it for over a year now, and I get that heat down here too and have had ZERO issues with it warm.  If you're still concerned though, give them a call--they will give you personal attention to answer your question!

Not sure how much this will help but try freezing the bottles. I do this and by the time I reach for them they have started to thaw. Easily will be thawed out in three hours. The freeze should not hurt the mix. I usually mix mine up the nignt before and stick them inthe freezer. Actually saves time this time of yeear as I can mix a few days worth and just pull as needed from the freezer.

x2 on the freezing.

I use Perp on the bike and infinit on the run.

I plan to use a "hot&cold bag" Found it at the grocery store cheap. It will fit in the SN bag along with some ice. Should keep things could enough till I get there.

Infinit does not sour when warm like perp.  It just tastes better cold so I mix bottles as I need while training.

I have trained with my mix warm, that way there will be no surprises on race day. I mix mine in 10oz bottles on my fuel belt (3 on my belt) and carry a water bottle in my hand. I will have 3 more at the SN station as well). I take 2oz sips every 2km and wash it down with the water (1 10oz bottle = 1 Hr) I carry the third bottle  "just in case" Im out there longer then I plan). This worked great at my HIM last weekend. As I ran by the water stations I just yelled for water and topped up my bottle. This gave my plenty of cold water on the course to soak myself as well as drinking whenever I wanted.

I've hear of people freezing them.  Also wrapping them in insulated packaging.

If you freeze, make sure the pop up top is closed!     would be a mess when it starts to melt in your SN bag

Another alternative is to just mix two 3 hour bottles and carry them.  That's what I did, with a 3d emergency bottle in SN.  Once the first one was done about half way thru, I ditched it.  this was on flat IMAZ so may not be preferable depending on the race.  But any extra time caused by an extra bottle was washed with stopping to get a SN bag and filling/mixing your bottle -

keep in mind, there may or may not be an aid station with water right at the SN stop, so it may require two stops.

FWIW, Infinit is okay tasting warm.

i use polar insulated bottles and mix (4hr concentration) them night before and put them in freezer (they don't freeze, just get cold). then place in bubble wrap and into SN bag...i did IMKY last year and it was kinda warm (not as warm as IMWI 05 though) and the perpetuem was cool/cold when i got to SN on the bike. worked great.