# Bubbles...



## Tinkstar (Nov 27, 2020)

So this coffee has been sat for a month since roast. Easy may be 6 weeks. Still in date. Opened it this week.

When I add milk, do my art, 30 seconds or so after I get lots of bubbles, destroying the art.

It happened all the way around but I was too slow to take a picture but you can see the last one and the lasting effect.

Whats this from? Milk? Coffee?

Spoils my art work 🤣


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## dutchy101 (Jun 12, 2020)

Sure I read on here it's down to beans degassing. Would have thought they'd be well done after a month


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## Tinkstar (Nov 27, 2020)

dutchy101 said:


> Sure I read on here it's down to beans degassing. Would have thought they'd be well done after a month


 That's why I thought I'd ask..


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## DavecUK (Aug 6, 2013)

@Tinkstar looks like it might be from the milk


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## Rob1 (Apr 9, 2015)

It's from the calcium carbonate in the milk reacting with H+ ions in the coffee to release carbon dioxide.

Or to put it another way it's the milk reacting to the acidity of the coffee.


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## Like Medium Strong Coffee (Feb 18, 2021)

Rob1 said:


> milk reacting to the acidity of the coffee.


 Is it beans dependent or a function of extraction? Could you explain with some examples please, as this doesn't happen often? Thx


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## Rob1 (Apr 9, 2015)

All coffee is acidic, some more than others so you'll see it happening with all coffee to different extents. It will be very much related to steaming too and the consistency of the milk. Put ordinary unfoamed milk into coffee and you'll probably see some small bubbles around the rim of the mug but nothing like you see in the image.


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## Tinkstar (Nov 27, 2020)

Happens all the time to my knowledge but more commonly really small bubbles, tonight had some large ones 🤷‍♂️ which prompted my curiosity 😁


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