Crema question - gaggia classic

[DomCoff]

Please excuse my ignorance, or if this is posted anywhere before, but Ive got a general question the thickness of my shots with a gaggia classic (with pressure mod) and isomac grinder.

My question is how thick should the crema be with a shot? Ive read around that the crema should be generally about 3 mm in general (not taking into account the age /type of beans used, grind type... etc)

Im only wondering as Im using a quite fine grind, espresso dark roast beans, a correct 25-30 shot, but tamping quite hard (and polishing/ tapping), and filling the coffee in the portafilla so it fits in snugly... Yet, my pucks are watery... If I change to anything less (eg less coffee, less grind fineness, or less pressure while tamping, my shots are too quick and the crema is too light coloured and thin)

This is about as thick as my crema gets, especially when trying different types of beans, roasts, and even home roasts...

Oh, and Ive also tried heating/ not heating the pf, glasses and allowing the boiler to be on for about 1/2 hr before pouring...

Also, does the crema supposed to change colour if it sits for a while, as mine gets darker the longer it sits...

Anyway, any help would be greatly appreciated.

Thanks

Dom

[yeeza]

Re: Crema question - gaggia classic

That 3mm crema is IMO uber-general. The crema will depend a lot on the freshness of the beans (how far post-roast they are), type of bean and type of roast. Darker roasts seem to not have as much crema too. Find out how hard you are tamping too - even if it means getting out the bathroom scales and practising on that.
As far as how much coffee youre putting in, I used to put as much in that it would leave an imprint of the shower screen screw in the puck.
First off reading your post kinda lends me to think that the beans you are using may not be as fresh as they could be. Where are you getting your beans from?
If your pucks are watery, maybe your grind is too fine?

What type of grinder are you using?

Heating the pf is a good idea, leave it in while warming up the machine.

Maybe Lucinda has a few more tips
Let us know how you go.

[DomCoff]

Re: Crema question - gaggia classic

Grinder Im using is an Isomac grinder mentioned on this page, pictured here http://coffeegeek.com/reviews/grinders/isomac_grinder
Set on the 2 down from the finest setting it can go. (Im not sure of the setting, as I knocked it over, and the setting disc popped off, but I couldnt remember what number it was on, so I turned the dial to one of the grinding end and put the disk back on)

As for beans, well thats the thing, Ive used a range of beans, from supermarket bought, speciallist coffee shop bought, home roasted... Varying in darkness from light-medium roast to dark roast (espresso)...

Should I be getting more crema with these, or is the 3-4 mm of crema about right?

Should I post a pic of the shots?

What about tamping pressure... whats the best tamp pressure? I get conflicting results with that too...

About tamping: For me its more of the method... what I do, is partially fill the pf, shake it even, refil to top, level with finger, tamp lightly, tap on sides, then tamp again north, east, south, west while polishing, then polish again lightly around inside edge of pf (so the coffee doesnt form any gaps between edge of puck and pf...

Am I over tamping?

Dom

[>pullman]

Re: Crema question - gaggia classic

Hi Dom,

I would expect more crema than you are getting - when you use freshly roasted beans that is.

Re tamping... yes you are over tamping in my opinion.

Firstly the tamp pressure should be about 13.5Kg (try on a set of bathroom scales) when using normal baskets - like you are using.

Secondly every time you tamp (after the initial tamp) you set up "fracture lines" in the puck - weaknesses where the water will flow as there is possibly a break in the consistency of the puck (water always takes the esiest route)...

You need a better fitting tamper (not just because we supply them : - other brands are available as well) - that will allow you to tamp the whole puck in one action without the edges having untamped coffee grinds..... You dont really need to polish but if you choose to - again once and once only - after the tamp - and just using a little pressure (the weight of the tamper if it is solid is enough).

Hope that helps

Robin.

[lucinda]

Re: Crema question - gaggia classic

Hi Dom, thanks for the PM and I will answer here.

There are a few variables. If you are getting a wet soggy puck, you need to updose (add more coffee) to the basket. You need enough that will touch the top screw attaching the shower screen. If you are using the double basket, aim for approx 20 - 21 grams of beans.

Like Greg said - Tamping is very important with the Gaggia. Get yourself a decent tamper. Take your basket with you to the coffee suppliers and find one that will fit the top of your basket snugly. If you can afford it, get on of Gregs. I have one of his tampers and noticed an immediate difference in my shots and no longer had to double tamp or do the NSEW method.With Gregs tampers you only need to tamp once and give a quick polish and thats it.

I do not know the isomac grinder so cannot comment on that, maybe someone else can.

Like Yeeza said, darker roasted beans do not give as much crema as a lighter (medium, CS10) roast. Cup size is another variable, If I use my large ACF cup I do not get a thick crema, yet when I use my smaller cups with narrower mouths, I get a thicker crema. Some beans do not give much crema, regardless of the roast.

How often are you de scaling and cleaning your machine? I sometimes notice crema issues when my Gaggia is due to be descaled. This needs to be done at least once a month using caffetto descaler. Do not use citric acid. Also, remove the shower screen and soak that in cafetto solution and give it a good scrub.

Water can be another factor. I am in Adelaide and only use rainwater/springwater or filtered water as our water is very hard and causes scale build up.

Finally - how does the shot taste? That is whjat is most important. If you are getting a good flavoured shot, that is what is important.

[DomCoff]

Re: Crema question - gaggia classic

Thanks lucinda,

I really appreciate it... and everybody else at that too...

Ok, I forgot to mention that Ive ordered a tamper from Gregs (included my basket), also I use spring water only...(aqua pura due to less minerals--- but thats probably being a little anal about it) Ive never used Adelaide water in it, due to the scale buildup, and it can give a disagreeable taste. From what I pull now from the machine, the taste is full bodied, non-bitter but slightly velvetty and a little thin. (From the medium- darker roast)

Descaling... Thats something Ive sadly havent done regularly... (Im so disgusted in myself about it... I meticulously clean the shower head, removing screw and cleaning it every month or so, but I was very concerened about what type of descaler to use, as Ive heard so many conflicting reports about types to use... Thanks for the suggestion of type... Ill get that one...)

Ahh, cup too... I know it sounds really silly, but I usually use a shot 200 ml fluted drink glass to measure my crema, as Ive used a specific espresso shot glass, and the crema amount is the same...)

I know it sounds silly, but a friend of mine purchased a cheapy auto machine (saeco) and pulled a shot from store bought pre-ground very dark coffee, yet the crema was quite dark and very plentiful, but coffee had a bitterish, awful taste. Although, he was using a pf designed for store bought pre-ground that on the inside had the usual amound of holed, yet on the outside only had 1 outlet hole... Ive never seen those pf before, yet the crema was as plentiful as what one gets in usual commercial machines... Now I thought that if he could get that much crema from the store bought garbage, what was I doing wrong???

I do have to admit though, not to sound blow my own horn but my shots were certainly more full flavoured, had more depth, but alas didnt have as much velvetty, mouth feel as his did...

Anyway, thanks again lucinda and everyone here for the advice... Im looking forward to trying that tamper from Gregs... Now I just have to chase down that descaler Lucinda mentioned...

Dom

[JavaB]

Re: Crema question - gaggia classic

I know it sounds silly, but a friend of mine purchased a cheapy auto machine (saeco) and pulled a shot from store bought pre-ground very dark coffee, yet the crema was quite dark and very plentiful, but coffee had a bitterish, awful taste. Although, he was using a pf designed for store bought pre-ground that on the inside had the usual amound of holed, yet on the outside only had 1 outlet hole... Ive never seen those pf before, yet the crema was as plentiful as what one gets in usual commercial machines... Now I thought that if he could get that much crema from the store bought garbage, what was I doing wrong???


Dom

Dom,

You arent doing anything wrong - they have a machine with a pressurised basket - as you say, designed for stale store bought.

The coffee is forced through the small outer hole under pressure where it is mixed with air... causing it to froth up..... just like texturing milk....

It is NOT true crema!!!! It is frothed coffee..... looks pretty good (maybe :) but tastes like..... :P :P

[DomCoff]

Re: Crema question - gaggia classic

Cool, thanks JavaB, that puts my mind to rest...

My next course of action is to get some descaler, and give my machine a good clean out... and after that possibly by a rancillio rocky doserless grinder, as the isomac Ive got is giving me a bit of grief... Ive had it for a few years, and think its time to go one better...

Dom