Can liquid feeds go bad?

molly1205

Can a bunch of plastic bottles filled with carb drink go bad if they are sitting in a kayak in the hot sun all day? I wouldn't think so, since it's just a mix of carb powder in water, but thought I'd check with those of you who've been there, done that.

david_barra

The short answer is yes... mixes that contain protein (especially whey protein) can turn foul in a couple of hours

evmo

- Whisky Stones
- Polar Bottle

ChickenOSea

Holy crap! I never thought of using those stones. Good idea! Thanks

dc_in_sf

evmo wrote:

- Whisky Stones

You are by far better off using ice to chill things than whiskey stones. The main chilling effect of ice comes from the latent heat of fusion - the energy required to melt the ice.

A gram of ice at -20C (temp of a domestic freezer) requires ~40J of energy to get to 0C and then 334J to melt and then a further ~80J to get to 20C for a total of ~450J (the heat capacities of liquid water and ice are different)

A 1 gram whiskey stone at -20C needs ~40J to go to 20C since there is no phase change. Soapstone is ~3 times as dense as water so a stone the same size as your ice cube would need ~120J.

Whiskey stones are only valuable if you are worried about diluting the liquid that you are trying to chill, and I am not sure that is a prime concern with feeds.

evmo

@dc_in_sf, I'm sure your physics is correct, but... actually some people might be concerned with dilution, which is why I suggested whisky stones. Obviously, ice is also much cheaper than whisky stones.

I calibrate my feeds very precisely re: caloric intake per volume of liquid, and I prefer that it remain constant over the course of multiple feedings. So dilution matters.

Personally I've never used stones for swim feedings (only scotch). I find it sufficient to start with cold liquid and then keep it cold with an insulated container. But I would never use ice - precisely because of the dilution effect.

molly1205

Thanks for the feedback. I'll be sure to keep the bottles cold - or just forget the whole thing and drink whiskey.

loneswimmer

Along with what @Barra says about protein feeds, and answering your question specifically I think, carb feeds can also go off by starting to ferment using any bacteria in the bottle. You slow this by sterilizing your bottles and of course, keeping them cool.

gregoc

Yes, to feeds with protein (Perpetuem, etc), but not likely for straight maltodextrin (CarboPro). Bacteria can break down maltodextrin (that is what happens in your gut), but the bacterial growth and breakdown of maltodextrin in the bottle would be minimal over several hours or even 12 hours. If you are swimming in cool water have the kayaker float the bottles off the side.

Dawn_Treader

Hi Molly,

I am not an experienced OWS. But I'm using my same fueling methods now as an OWS that I used in triathlete. I used to make thick portions of perpetuem in my bottles, fill them half way and throw them in the freezer. I added tap water and filled them up in the morning, so when I had long training or races in the height of summer, I never had problems even in races of 30 degrees. Good luck with your goals!

molly1205

Thanks for the input. I'll talk with my kayaker tonight to see if we can put the bottles in a bag of ice. And, freezing the bottles half full is a great idea!

JBirrrd

Just Googled whiskey stones....such an education, this forum:-)