Hm. I've had banana-only smoothies before, and they never foamed up.
Try using less water. You don't need a lot to blend bananas. They turn to liquid with barely any added water (a few tablespoons). Also, if it's okay on a stomach tube, try adding some ice.

yea and maybe try blending it for a very short period of time. try it for a few seconds, stop it, and another few seconds till it's done. and liquid isn't really necessary like schrip said. another strategy is to leave the blended bananas out for the bubbles/foam to subside.

If your bananas are as ripe as they should be - lots and lots of brown spots - you don't need water to blend - and they have to be ripe for you to get all their goodness. Add water to your ripe blended banana and stir til smooth . Keep adding water a bit at a time and stirring - stirring with circular action, not a whipping action - til it is liquid enough for your tube. Other foods that get lots of air blended in might benefit by adding a simethicone tablet before ingestion. Should not be necessary with your bananas.

You made me remember reading this about the vitamix (oh, I want one!) but I think it should apply to most blending. Hope it helps!

The following was taken from: http://community.vitamix.com/service/displayDiscussionThreads.ki...

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Tip 1 from Lea Ann Savage - Vita-Mix Demonstrator

I learned this a few shows ago from an audience member who had called
Vita-Mix Customer Service for help because their juices were too "foamy".
Now, I teach it to all of my audiences in my demo while I'm doing my
(previously foamy) Emerald Ecstacy (which I now call "Shrek Juice" when
there are kids around).

Tomatoes, Pineapples, and Oranges all tend to get foamy...

After you have blended the drink on high, switch to variable speed #1;
look down into the container from above (as long as you keep it on
Variable at low speeds you can take the lid off, but be careful - if you
have the lid off and the switch gets flipped to high, you will redecorate
your kitchen!)

Anyway, as you are looking down onto the liquid, work the speed up slowly
until the moment you see a small vortex "hole" in the center of the
liquid. Stop at that speed and let the juice spin for 30 seconds or so.
After a bit the air bubbles will pop out of the drink and the hole of the
vortex will get bigger, lower the variable speed again to keep the hole
small for say another 30 seconds or so. By then you should be "foam
free"!

Tip 2

A member of our previous group used a gravy separator to get the foam out
of his soups.

After blending, he would pour the soup into the separator and waited a
bit. The foam would rise to the top and he could then pour out the foam
free soup, leaving the foam in the separator.

I've never had that happen to blended bananas, but it does with tomatoes if I blend too quickly or over blend. Instead of blending, try gently pulsing the bananas until they are half way smooth and then switch to a low setting until completely blended.

Oh, and make sure your bananas are fully ripe (completely yellow with brown spots)! This should make them very easy to blend. :)

HTH,

Swayze
www.fitonraw.com

Thanks everyone. I used riper bananas this time with almost no liquid, and it worked tons better. Of course, I got my Vitamix today :):):):) and was using it instead of my old blender so maybe that made a big difference too.