Powder to flavor water.

[Andy BB]

Berocca? http://www.berocca.co.uk/en/products/berocca/index.php

 

[Everything Mac]

I love screech, so does Wayland... we always have a few sachets buried in the pack

I love it as well. A very kind soul gave me a bag with twelve sachets in it. I hide it in the loft so it's about 4 months before I find it again.

There are powdered energy drinks no?

 

[TurboGirl]

Tesco sells Kool Aid

And if you want to double up useage, it's a rampantly good and easy dye stuff too (natural fabrics, instructions from Knitty here, it even works on human hair if you want to do your own without the usual chemicals )

 

[Graham_S]

Tang is available in single serving sachets.
I use it in the summer to make water a bit more palatable.

 

[Hypnagog]

Not a powder, but easy to carry in the kit is this stuff:



http://www.tesco.com/groceries/Product/Details/?id=282138037

I'm not sure that I'd make it last for 20 servings though.