Newbie using a presso - need help with troubleshooting shots!

Beginner and pro baristas share tips and tricks for making espresso.

#1: Post by guosh »

Hi everyone,

I'm really new to the whole world of Baristas, espressos and basically coffee appreciation - I had my eyes opened a week ago upon visiting a nice small cafe in Singapore, and have been trying to read up as much as I can at the moment.

I thought I'd start from the basics and the use of a Presso to extract a single shot of Espresso. However, after reading through this site I've not been able to replicate anything even close to the shots that everyone here has posted.

At present I'm using freshly roasted beans entitled 'Colombia' from my local cafe which they helped fine grind for me and tamping it using David Schomer's pressing technique. Water has been freshly boiled and left to cool slightly (about a minute at a room temperature of 36C). After which I'd fill it to the double shot level and extract a single shot worth in about 30 seconds with a smooth press of the levers.

My problem is - my shot is entirely black, thin and with little or no crema. What can I do to improve? Is it a pressure problem? Because I see cracks on the top of my puck after removing the portafilter from the machine (the bottom's fine though).

Any suggestions before I suffer an overdose of caffeine from testing shots on myself? :mrgreen:

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#2: Post by aecletec »

Coffee really needs to be ground within a few minutes of use. Otherwise you can kiss crema goodbye...
The crema isn't particularly spectacular on my presso (well, it can be but then the flavour suffers) but the flavour is very close (to my palate) to what I get in a cafe using their coffee.

The water cools in a presso quite fast, it acts like a large heat sink. I would not let the water sit at all, I pour from a rolling boil into a pre-heated presso.
See below: my pre-heat routine takes several minutes - I scoop boiling water from the saucepan into the presso and it trickles back down (I prep the basket during this time).

In my opinion, for this method silicone tubing is necessary for food/heat safety.
In a test of concept I used food grade pvc but it turned opaque and warped...

This is a lot less messy than what I used to do - juggling water between two jugs and a stovetop kettle. Prior to that I plugged the spout and filled it with boiling water, but that cooled too quickly.

When the presso is too hot to comfortably touch it's about ready to my taste for darker roasts, otherwise the shots can be sour. For lighter roasts I don't heat it up as much.
I then place the prepared basket into the portafilter and use fresh boiled water for the shot.

I also pour in much more water than up to the double line - I lift the arms slightly, start pouring until it's about 3/4 full, raise completely and then press.

guosh (original poster)

#3: Post by guosh (original poster) »

Thanks Chris, I'll give it a shot tomorrow morning.

In your experience though, is the additional water really needed? I tried it this morning and I was afraid I'd break the levers due to the resistance. Also, the cracks in my puck made me think I was using too much pressure but I'll try again hopefully with new beans as well.

I was under the impression that the crema acts as a signifier of the espresso quality, especially since I've been trying to look out for the texture and color of the extract and the shots I've done are nothing like those I've seen here and elsewhere online - I was worried I was doing something fundamentally wrong.

Cheers and thanks for the suggestions regarding the preheating of the presso - I realize how much heat I'm losing now especially since my coffee is sealed and kept in the freezer. :mrgreen:

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#4: Post by aecletec »

I find that without the extra water it's difficult to get consistent / control the pressure... the air gets compressed and then the water comes out later... haven't had the best of luck with that and getting enough shot volume. With more water I can cut the shot when I like.
Also, unless the pre-heat regime is good enough I'd worry about the lack of heat retention due to the lower water mass...

If you're pushing so hard the levers may break I'd say your coffee might be too fine or you're dosing too much. I ground too find to begin with but have found that a grind for which a gentle (for a slightly stronger than average bloke like myself) smooth press giving roughly a 1ml/s flow yields good tasting espresso.

Well, I'm hardly the person to ask about crema... but when I have gotten the most crema on my shots they were a bit too concentrated for my taste (e.g. my typical shot may have ~1cm in a 90ml bodum before I drink it, ~30g from ~18g).
With a different machine, however, that may be a different situation. If you have no crema at all I'd be worried. Probably stale beans or - with the presso, I find if I let it pre-infuse or let the shot run for too long the crema is drastically reduced...

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#5: Post by mikekarr »

I like to use extra water as only a portion will flow through on one press. I do this because water does not compress as air does, hence increasing the pressure. That said, it's nearly impossible to get crema without freshly grinding the beans yourself. The gasses that create crema are long gone in preground coffee. Takes minutes for those gases to escape. Also, don't put that ground coffee in the freezer.

You can safely put the presso in the sink and let it warm under the hot water tap, it will work as well as anything else. You can then run a single shot of boiling water through before putting the grounds through. You'll be at a good temperature then.
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#6: Post by aecletec »

Why not put ground coffee in the freezer? Wouldn't it go more stale more quickly elsewhere?

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#7: Post by mikekarr »

It seems to dry more rapidly frozen after it has been ground.
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#8: Post by aecletec »

I don't understand what you mean by 'dry'... but if you've had experience with this and found not-freezing to be better, cool. What are your recommendations for storing pre-ground? Might be helpful for non-enthusiasts...

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#9: Post by HB »

aecletec wrote:What are your recommendations for storing pre-ground?
My wife says the tomato plants in the garden like the acidity of ground coffee. :)

Seriously, beyond a few minutes, the oils evaporate in preground coffee, making it difficult to dial in the grind. In my experience, the result is thin, dark, bitter espresso if pulled short; thin, sour, blond espresso if pulled anything approaching double volume. That said, I've made French press with preground coffee for camping and it's worlds better than the instant drek most campers call coffee. I store it in a sealed container.

Searching on "preground coffee" will yield other discussions/advice.
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#10: Post by aecletec »

Oh yes, there's a good reason why I have a grinder ;) hopefully your input will help convince our friend to get one!
I only bulk grind beans I'd otherwise throw out... Those I've given them to seem fairly impressed, however, compared to their usual fare. Will check out that link, thanks.