Air in extraction process? EM7000

[samnz]

Long time googler, 1st time poster!

Can someone tell me what causes air in the extract? The coffee tastes ok, but the extract looks like a milkshake! It makes a loud hissing sound when extracting as the air p***es out. This only happens on double cup shots too. Haven't had with single.

I have a Sunbeam EM7000 at work and at home, and never have a problem at work. The only difference in the 2 environments is the grinder - the EM0440 at home and the EM0480 at work. https://www.sunbeam.com.au/en/Produc...=EM0480,EM0440

I can't get consistency with my extraction at home. It makes me think my grinder sucks. Even if I stuff up the tamp at work, the coffee is still reasonable. At home if i don't tamp perfectly it either floods like a tap and tastes like mud water or the machine haemorrhages and doesn't extract at all, due to too tightly packed grind.

Beans are hummingbird 'crave' at both locations.

I would appreciate any input!

/sam

[smokey]

samnz, how longs does your 'pissing and hissing' extraction take? If its very short then its grind is too course and this could be your initial problem. But then you say it also freezes up and won't extract, so all in all that sounds like a grinder problem. I don't know the 440 but at $99 I think you are due for a decent grinder, the 480 does a fine job for its price, if you can afford it get a better grinder, and please let us know how that goes.

[Ronin]

Air or gasses in the shot could bee a few things. Too fresh beans, channeling or the basket or machine seals is where I would start looking.

Too fresh beans will have lots of gasses in them from the roasting process, best left to rest for at least a week IMOP

Do you use pressurized baskets? If so it could be split and leaking

[Journeyman]

If it's only in the double that suggests the basket is the problem. Leaks elsewhere would affect all shots. If you're not getting water on the bench it's unlikely to be inside the machine, but take out the water container and look. Almost any leak in the water path will result in water coming OUT not air getting IN due to the pressure.

Do you get hissing with an empty double basket? Try pouring an empty shot and see what gives. Maybe also let it run without the PF for 60 secs and see if the water changes.

Ronin's Q is relevant - are you using a pressurised (double-floor) basket for your doubles? Try using the single floor one instead.

Also does the 7000 PF have that black plastic shield they put in the 6910 PF? Take it out if so.

[samnz]

Guys, thanks so much for your replies!

I did another single and it was a good pour with no air. I then used the double basket, and used a finer grind. It didn't hiss until the end. I youtubed it just to show you. (Below)

Funny you should mention the basket, as it isn't exactly the same as my workplace one. I might do a sneaky swap for a day and see if my colleagues moan about hissing

There is no plastic shield like on the em6900.

What does "channelling" mean? The double cup I have is dual floor, the single is not.

There is no leaking and the tank looks good.

I just ran an empty pour and it still hisses! Great tip there journeyman. Can't blame my grinder now.

http://youtu.be/wRnxC7h_-Jc

[samnz]

I just replied via tapatalk on the iphone and it seems to have lost my long winded reply

Thanks for all your replies!

samnz, how longs does your 'pissing and hissing' extraction take?

No more and no less than when it doesn't hiss at me. Haven't ever timed it but can say it's roughly ok.

Too fresh beans, channeling or the basket or machine seals is where I would start looking.

What is channelling? Hopefully being a new machine, the seals are ok. The beans are a week old.

If it's only in the double that suggests the basket is the problem

Good point.

If you're not getting water on the bench it's unlikely to be inside the machine, but take out the water container and look.

Tank ok, no water on bench

Do you get hissing with an empty double basket? Try pouring an empty shot and see what gives.

It still hisses with empty basket! Didn't expect that :|

are you using a pressurised (double-floor) basket for your doubles? Try using the single floor one instead.

The double cup is pressurised and the single is not!

Also does the 7000 PF have that black plastic shield they put in the 6910 PF? Take it out if so.

No, doesn't have that shield.

I ran a finer grind and there was less hissing, but still there - here is an example - https://www.youtube.com/watch?v=wRnxC7h_-Jc

/sam

[Barry_Duncan]

Sam.

Welcome to CoffeeSnobs.

Channelling is not so much to do with your machine but due to your dosing and tamping. It is when the water channels unevenly through the coffee grounds resulting in weak coffee due to uneven extraction. Many of us use a naked or bottomless portafilter where channelling shows up as squirts in all directions. These are not obvious with the standard portafilters.

I see that I have reached 1,000 posts in 4 years.

Barry

[samnz]

Thanks for the explanation Barry. I will obtain another PF and see how that goes.

[Lukemc]

That's the sound of a pressurised basket in a portafilter with no insert I'm pretty sure. I've seen it happen with a 6910 after taking the plastic insert out and having a workmate use a pressurised basket

[MrJack]

How much coffee are you putting in the double, and how sure are you they were roasted (not purchased) a week ago?

[samnz]

Yea bean purchased a week ago, not roasted a week ago.

Are there any disadvantages to using a non-pressurised basket?

[MrJack]

I'm going to guess they're quite a few weeks post roast, judging by the video.

[saoye]

You only showed 12 seconds of the pour and the entire time it's watery and blonde...what was the start like? Probably best to show your entire process for us to pinpoint the problem. A few possibilities includes:

Stale beans
Under dosed
Too coarse grind
Channelling

Amongst other things

[samnz]

@saoye it wasn't a great pour you're right, it was under dosed that time.

I am going to grab a non-pressurised double basket tomorrow and see how it goes.


I made one of my best coffees this morning, using 2 single shots, finely ground and lightly compacted