Naked Portafilter spatter

[MarkJames]

Hi,

This is my first post here though certainly not my first visit. In fact, my most recent coffee purchase (a Quickmill Andreja Premium) was based partly on the reviews and opinions here as well as on some information from Sweet Marias (another site that I can browse for hours)

Anyways - thanks for the wonderful information and a quick question.

I was very taken with the 'espresso porn' and want to do 'that'. I quickly found that there are a lot of variables. There was no way for me to ensure that my tamping or extractions were right. Further, I've been roasting my own coffee for a couple of years and while it tastes great to me I was unsure if it was a good roast for the purpose. So.. I bought some Black Cat beans to take that variable out of the equation. I've got a Mazzer mini so I'm pretty sure I've got a good grinder for the job but what exactly the grind was I was unsure of.

To make a long story short - I bought a bottomless portafilter in order to help the learning process. I've got the grind on the mazzer at about where the factory seems to recommend for espresso. This coupled with tamping at about 30-40 pounds seems to result in about a 30-35 second 2 ounce extraction. Using the bottomless portafilter I can watch it happen and it looks pretty nice - mostly centered - seems to get some of the tiger striping (though I don't have as much light as the videos here so it's hard to tell). The unnerving thing is get little tiny bits that spray off in many directions and make a real mess of the espresso machine. The spray is very fine - almost a few bits of mist. Not what I'd call channeling (at least from what I've seen of the videos posted here) but it's definitely there. Is this normal or should I be addressing this?

Thanks!

Mark

[another_jim]

They're called spritizies, the espresso extraction equivalent of gremlins and bugs.

Everybody gets them when first using a naked PF, even people who think they are good shot pullers. It's quite a humbling experience. The good news is that if you stick with it, your technique will become good enough to see them only very rarely.

The big technical lesson learnt by everyone who uses a naked pf is "distribution," that is, making sure your ground coffee is evenly distributed, clump free, and of equal density throughout the basket before tamping (look for the posts). Turns out that this is more important than dose or tamp for getting proper extractions.

There are quite a few techniques people use, going from casual to quite tedious. The one that will work for you depends on how gentle your group is, and how clumpy your grinder.

[MarkJames]

..... It's quite a humbling experience.

lol - thanks - spritzing - that's exactly what it looks like!

This whole aspect of coffee enjoyment is a humbling experience. I've had super-automatics for a few years now and just recently moved on to where I can take more control of the process myself rather than trusting it all to a brew group behind a metal door.

The biggest problem with getting this far into coffee geekdom is how hard it is to go out for coffee anymore without criticizing most everything you see.

Mark

[HB]

The unnerving thing is get little tiny bits that spray off in many directions and make a real mess of the espresso machine. The spray is very fine - almost a few bits of mist.

In addition to assuring an even, clump-free distribution, verify that the brew pressure is a reasonable 8.5-9.5 bar. I produced this nice spritz by neglecting these and raising the brew pressure to 11 bar:


From Perfecting the Naked Extraction

[MarkJames]

I checked my pressure and it is, surprisingly, exactly in that range.

Is that pressure reading machine related? or is it more a factor of grind fineness and how tightly the puck is packed?

Mark

[cannonfodder]

Which range 8.5-9.5 or 11 bar?

[MarkJames]

ok... my newbieness is gonna show a bit here...

I have an Andreja premium - there are two gauges. The top gauge seems to be the pressure in the boiler the bottom gauge seems to read the pressure downstream from the pump during the extraction. My boiler pressure sits about 1.2bar - the pressure during the extraction rises to somewhere about 9bar and stays there for the most part of the extraction process. What I was wondering is if that 9bar reading is adjustable or if that's just a result of the coffee puck.

Mark

[HB]

What I was wondering is if that 9bar reading is adjustable or if that's just a result of the coffee puck.

Jim Schulman's diagram explains it well:



Thus the brew pressure gauge indicates the lower of the (a) pump output, (b) puck resistance, and (c) over-pressure valve. Chris Coffee's FAQ has pictures and instructions under Andreja Premium & Anita: Adjusting the brew pressure.

[MarkJames]

wow... very helpful!

Thank you very much

Mark

[cannonfodder]

9 bar is right on the money for brew pressure. You can adjust it, but it is not the cause of your spritzing. The other gauge is your boiler pressure. Boiler pressure and temperature are relational, the more pressure, the higher the temperature. Again your 1.2 bar is just fine.

Your channel jets are not being caused by a setting on your equipment but by a defect in your distribution/tamp. As Dan likes to say, the problem is on the handle side of the machine.

I did a video with some distribution techniques. You may want to give it a look just as a point of reference, then practice practice practice.

[MarkJames]

Thanks,

Lots of improvement happening already. I can't manage the Stockfleths move - my portafilter seems to be too hot. It's probably because I'm learning and so going slowly - perhaps I should practice with one that's room temperature. The videos are tremendously helpful - thank you. Reading is one thing but seeing is much more.

Mark

[cannonfodder]

You will eventually develop 'portafilter hands' and it won't be a problem. The first month or two can be a bit hard on the hands and fingers.