Dr Brown bottles leaking in odd way! What am I doing wrong?

[Trillian42]

Bizarre question I know, but I figured if anyone could answer it, Mumnetters could...

We have 2 sets of Dr Brown bottles, bought at different times so not just one faulty bottle. Both seem to leak when we're heating the formula in water... standing upright!

So bottles are on side in fridge, not leaking and then we take them out, put them upright in warm water and then they leak. We're using the lid thing below the teat. They have hardly any formula in them so it's not that they're overflowing. We lost 40ml out of 120ml just now, so it's not a small amount.

Are we doing something silly to cause this?

This happened to us. We just put them in water without the teat and it stopped.

What a design flaw so!

Thanks for the response :)

After warming I would unscrew the lid and let the air/pressure/whatever the hell it is out then screw lid back on and they wouldn't leak. Lots plenty of hard worked for breastmilk before I figured this out!

Actually it happened with other bottles too...my DH told me why but I've forgotten . He probably chose to wake up and tell me at 4am

I used to take the top / teat off too and it wouldn't happen.

Mine always leak too - v annoying. I think it's something to do with the air return holes in the brown valve.

By changing the temperature of the milk and bottle, you're changing the pressure in the bottle. You can often see a barometer like line in the tube. Once heated, undo the screw and dislodge the brown bit and put it back together and the pressure should equalise and the leak not happen.