Gaggia Classic: First couple of seconds of the shot look almost black
I am having a bit of trouble with the shots that I am producing. Every time the first couple of seconds of the shot, the colour is very dark, almost black. After that it changes to a lovely rich chocolaty brown colour which I am pretty sure is what I should be going for. The shot itself has a bitter taste to it. Am I burning the coffee at the start? I have tried to mix and match the grind a bit but find if i go less fine then the only thing that changes is the flow but the first part is still quite dark and after the colour isnt as rich and looks a bit washed out.
Any advice you have would be greatly appreciated.
Does it start off drippy? How long after the first drips does it form a coherent cone? What volume (or better yet, weight) are you getting in what period of time?
Are you using a pressurised basket (one hole in the bottom) or a single-walled basket? (same number of holes viewed from either side) How many grams are you dosing, roughly?
What beans are you using, and with what grinder?
Don't stress about the colour. Get the volume/weight/time in the ballpark and then start tweaking to taste. Look up temperature-surfing if you haven't already and leave sufficient time between shots (5-10 minutes, without intervention); unmodified Classics are a bear in that respect.
Bit hard to say without seeing it. The description of the pour sounds normal without understanding timing of the shot.
How long before you get the 'blonding' (watery, washed-out appearance).
Has it been like this before?
What coffee are you using? Is it freshly ground?
Dragonuv21 and Flynn have covered most of it, but here's my two cents worth.
First, the two things you have mentioned may not be related, and should be considered separately.
The colours of the shot seem normal to me (for a Gaggia Classic anyway). I have three, of different vintages, and they all start to pour very dark brown - almost black with some beans - then get lighter as the pour progresses. I have little experience with other machines, but for me this is normal.
As the others have suggested, the bitterness could be caused by several things, the beans, the temperature or over-extraction just to name a few.
One simple thing you could try is completely ignoring the time factor, and stop the shot earlier than you have been doing, well before it begins to 'blonde' and see if that reduces the bitterness. If it does, then you can follow the advice above and start tweaking your grind/dose/tamp.
If it is still bitter with a shorter pour, then you will have to consider all the other possibilities.
P.S. If you are comparing the colours in your pour with videos on youtube et al , remember that they may have used much lighter roasted beans, or the colours could have been washed out by bright lighting.
Last edited by deegee; 21st March 2014 at 10:28 AM.
Reason: See P.S.
An article that I have found helpful in understanding the various colours and stages of extraction can be found here: Diagnosing Espresso Extraction Problems - Espresso Guide • Home-Barista.com Based on this article, your experience is probably about right. The bitterness you are experiencing could be as a result of overextraction (too much of the light coloured part of the shot at the end). The darker part at the start of the extraction is more likely to be giving an acidic flavour.
As deegee suggests, it's probably worth ending the shot earlier based on colour and see if that makes a difference. You could also see what the stuff at the end tastes like on its own to see if this is where the nasty flavours are coming from.
Thanks for the comments. I am using a single walled basket as, The beans are Merlo Australian blend that I grind myself with a Breville smart grinder. I will read through the guide posted and do some more experimenting. For now, here is a video of my standard pour. Any feedback would be most welcome.
WP 20140322 0051 - YouTube
It's that thing you're doing where you switch the machine off after five seconds for ghetto "preinfusion", when all you're doing is smashing your puck to hell.
Stop doing that thing.
(When you turn the switch off, the positive pressure on top of the puck is vented out through the discharge solenoid, which sucks air up through the basket and puck. You're basically ensuring that you get massive channeling).