Sister went nuts over a cup of coffee

Are you sure this is just about coffee?! Sounds like this was just an opportunity for your sister to lose it with you and your husband to join in!
Text your sister not to come over anymore and have firm words with your husbands about his behaviour…

I never fil to top as I spill it everywhere. She was extremely rude

I’d love to hear the other side of this.

Me too, but a surprising number of people seem to be under the impression that if you go round someone’s house you should expect five-star service and every whim anticipated and catered to.
OP, your sister sounds like my friend’s 10-year-old child with suspected ADHD and some trauma and boundary issues. She wouldn’t be welcome in my home again after shouting in my face and lunging at me.
My DP would also have some explaining to do if he joined in with childish bullying.

I think the coffee is the least of your problems here. The behaviour however is absolutely bonkers, now that would worry me, Definitely don't make her anymore coffee

What? Weighing water? Ummm... no.

Mind you I was bought up thinking Nescafe was posh and now get called a snob because I only drink instant if I really have to. But I but ground coffee, chuck some in the cafetiere and eyeball the amount.

Her behaviour was obviously way out of order, but my in-laws and husband do this with drinks too - they leave literally an inch or more to the top of the cup/glass. Wicks me off.

I have a bean to cup coffee machine and even a 'long' coffee only 3/4 fills a mug. I would rather have that than a completely full mug of instant. It's not rocket science to have a refill if I need it.
Your sister and husband sound extremely unpleasant.

Id expect a cup to be filled to .5/1cm from the top. My family would absolutely comment if they were less than that. And the fact your husband agrees with her means you must be under filling.

That said, neither of them should have treated you the way they did.

In our house we are jokingly petty with each other... passive aggressive humour. (But we all do it.) so she'd have a full cup next time... a cup, not a mug, in fact as smaaaaaall a cup as I could find, full to the brim with hot coffee. "Watch, it's hot", "don't spill it now", "hope it is full enough for you", "I know you like a full cup"... etc.. give as good as you get.

It's not the coffee.
Your sister and husband are bullying you.
Put a stop to it.

That "tea" is a crime.

I am struggling to make sense of this. None of it seems real!

Assuming it did happen, then DH is as bad as your sister.

I wouldn't be inviting her again, and if she has a habit of turning up at about the same time on set days, then I would be out at that time. Let DH make her coffee.

I have a full cup & don't like a tide out cup, but I certainly wouldn't behave as your sister did. Is your relationship like this generally?

DH got a bid carried away, didn't he. Does he act the dick regularly?

She actually ‘screamed’? Screamed in your face about coffee? Really?

That looks grim

Going against the grain here but I think you are pretty odd for repeatedly ignoring her requests for a full cup. Why not just give her the coffee she asked for or at least tell her to make her own? Seems bizarrely stubborn on your part.

What a ridiculous over reaction in the first place, and then to literally make a song and dance about it is insane.

It is also ridiculous that your DH joined in with her, why didn't he just stay out of it.

I am trying to picture the scene and honestly it's absolutely batshit behaviour from both of them.

Mil fills hers to the top, I fill mine to about a cm from the top depending on the cup or mug.

No song and dance ever ensues.

She sounds like the kind of person who thinks a big portion is a good portion.

I only really drink espresso so she'd it hate my house.

Last time she would be near my home.
Sister is unhinged and your husband a twat.

Never fill a cup beyond 3/4 way up.
Basic cop on not to over fill.

Text her that you need space.

Thank you for being the one to say that 😂. I was trying to work out what sort of tea it is because it’s certainly not a cup of “tea.”

Sounds like a storm in a teacup

I would probably have filled the cup about 85% full, but if I'd received a cup of coffee that was less volume than I wanted I might have asked for more up front or, if I was unsatisfied after finishing it, asked for a refill. Given how upset she became, it sounds like your sister was perhaps at the breaking point over something else, and I wouldn't call it "hysterics".

I would worry more about your husband as he performed over something that had absolutely nothing to do with him.

So this sounds like frustration boiling over after years of asking several times a week for a fuller cup.

Obviously she shouldn’t have behaved badly. But why can’t she have a decent size cup of coffee?

DM makes me use ridiculously small cups at her house. I want an actual drink because I’m thirsty, not a ration.

Exactly! I have no idea why people are chiming in in defence of the sil.