Heating EBM in mam bottles

[Whuut]

My DS is breastfed. I have started giving him EBM in mam bottles, he still doesn't always take it but thats another issue! My problem is I'm not sure how to warm the milk.. He is happy with room temp so if its recently expressed its fine but he won't take it cold straight from the fridge. I've tried immersing the bottle of milk in hot water but 1) it takes a while, and 2) the mam self sterilizing bottles seem to let water in the bottom. I've read you aren't supposed to heat it in a microwave but does anyone know why this is? Or has anyone done this?

Following as I have the same issue! We keep getting water in the bottles too. Baby won't take formula or any other bottle so really need a solution or I'll never get to be alone for more than two hours!

Can you heat the milk in whatever it's stored in? (I used storage bags which warmed up very quickly in hot water then poured into the bottle). Heating by microwave is fine as long as you make sure you mix it well before checking the temperature to ensure no hot spots. Mam bottles are fine in the microwave as they're microwave sterilising.

Microwaving is fine as long as you thoroughly shake it afterwards to get rid of any hot spots. Plus just heat it enough to take the chill off. Don’t microwave it for minutes on end.

Thanks everyone! I do store it in bags so will try that. And yes same @HeartboxTeddy my little boy won't take any other bottles, quite often not even these ones!

I microwaved mine with the teat screw loose, obviously shake well and check temp before giving to baby. They only say dont microwave because some people are a bit dim and wont shake it so it will have hot spots.
You can also heat in boiling water but you have to loosen the teat ring off or removed the teat ring completely otherwise it can draw water up but wont do this if bottle isnt completely sealed as it wont be pressurised

I always just fed from the tap, but DH is a lazy/impatient bugger and always microwaved. Just shake v thoroughly to even out any hot spots and test on your wrist before giving.

I warmed it in the bag (even from frozen!) and then decanted into the bottle - way easier than doing it in the bottle.