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Thread: Grinder causing sour taste?

  1. #1
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    Grinder causing sour taste?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I've been roasting some decaf wow from beanbay and thought I was having trouble with the roasting because I kept getting quite sour tasting shots. I had tried roasting it in many different ways but the sourness kept coming. I thought that sourness could be caused by underextraction but I was getting pretty good 30sec pours. I bought a naked portafilter and didn't find anything wrong, was getting good looking extractions.

    I have 2 grinders, one a compak k3 push and the other a mazzer mini. I've always use the compak for the decaf, but today I decided to try it in the mazzer. After settling on the right grind setting I couldn't believe the difference, at first I thought I must've used some other bean by mistake. No sourness at all, very nice taste. Seriously night and day. I thought maybe the extra couple of days since I last tried it might've made a difference so went back to the compak - but got a very sour taste again! Back to the mazzer; delicious!

    So I can't work it out. The extraction looks very similar. The decaf beans are very dark (and fairly oily a few days after roasting), perhaps CS11 or even 12. This batch taken just to second crack. I've always had to grind these beans fairly fine, even with the mazzer I found the right setting was a bit finer than other beans I use. With the compak it comes out quite clumpy, but the mazzer it's not.

    So any tips for when using the compak? Anything else that might be wrong? Machine is an expobar minore.

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    Quote Originally Posted by Agrajag View Post
    With the compak it comes out quite clumpy, but the mazzer it's not.
    Ok so I had a think about it and figured this was really the only major difference. I gave the compak another shot and this time stirred up the grinds in the basket to get rid of the clumps. Yep, much nicer shot. Not quite as good as the one from the mazzer but a significant improvement and at least it's drinkable now.

    My theory is that the clumps were causing small routes for the water to go faster through, so although it looked ok with the naked portafilter it wasn't really getting a good extraction.
    Last edited by Agrajag; 7th January 2016 at 09:56 AM.

  3. #3
    Rbn
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    And if clumpy, can we read fines, if so will they make it bitter?

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    Quote Originally Posted by rawill View Post
    And if clumpy, can we read fines, if so will they make it bitter?
    Sorry not sure what you're asking? It is a fine grind but I am getting good extraction times. I've tried grinding it coarse enough that I don't get the clumps on the compak but then the extraction is just way too fast and I still get a sour underextracted taste.

  5. #5
    Senior Member flynnaus's Avatar
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    I don't believe it's your grinder. Roasting decaf can be tricky. You mentioned you tried different methods. What kind of roaster are you using? Others may have suggestions for profiles they use.

    I haven't roasted decaf for a couple of years but, from memory,I found I need to be fairly vigilant to stop the roast from getting away from me. I try to anticpate FC to reduce the rate to about 3deg/min. if you have a temp probe, use the temprature to judge when to stop the roast, not the colour.

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    Quote Originally Posted by flynnaus View Post
    I don't believe it's your grinder. Roasting decaf can be tricky. You mentioned you tried different methods. What kind of roaster are you using? Others may have suggestions for profiles they use.
    I'm using a behmor. I've tried slowing it down after first crack, I've tried not doing so. I've tried P4 and P1 profiles with various bean weights. I tried copying various methods that people on these forums said they were using with decaf wow. Pretty much always got a sour taste which is what made me think it might be something other than bad roasting, which is why I tried it in my "non-decaf" grinder.

    But it was using the same batch, one after the other in the compak and then the mazzer that gave the vastly different results. Then stirring up the grinds in the basket improved the shot from the compak too. Maybe it's not necessarily the clumps, maybe stirring it is giving a better distribution in the basket or something like that (although using naked portafilter without stirring still looked ok, which is why I'm thinking the clumps had something to do with it)

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    It is just possible that the troubling grinder is not grinding the beans evenly. That is there are smaller 'fines' in the grind. This may contribute to the clumping. This would cause problem extraction that is more noticeable on sensitive beans.
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    Senior Member flynnaus's Avatar
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    Quote Originally Posted by Agrajag View Post
    But it was using the same batch, one after the other in the compak and then the mazzer that gave the vastly different results. Then stirring up the grinds in the basket improved the shot from the compak too. Maybe it's not necessarily the clumps, maybe stirring it is giving a better distribution in the basket or something like that (although using naked portafilter without stirring still looked ok, which is why I'm thinking the clumps had something to do with it)
    Fair enough. If you are getting better results from the Mazzer, that would suggest it isn't a roasting problem. Why not just use your Mazzer?
    Btw, have you tried grinding non-decaf beans in your Compak to see if there are similar problems as with the decaf beans?

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    Quote Originally Posted by flynnaus View Post
    Why not just use your Mazzer?
    I started using the two grinders so I didn't have to clean out the decaf beans from the non decaf (mazzer is a mini with doser), but now that I've found the decaf beans are actually pretty good tasting I'm not so worried about this. Maybe I will, but for now am getting good results with the compak + stirring

    Quote Originally Posted by flynnaus
    Btw, have you tried grinding non-decaf beans in your Compak to see if there are similar problems as with the decaf beans?
    I haven't yet, might give that a go just to see. The thing is that I have an idea my other beans will be ground coarse enough that the compak doesn't give clumping. But.. maybe it's not the clumping that's the issue. So will give it a go. Thanks!

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    Senior Member askthecoffeeguy's Avatar
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    Quote Originally Posted by Agrajag View Post

    The decaf beans are very dark (and fairly oily a few days after roasting), perhaps CS11 or even 12.
    .
    just a quick question - if the beans are very dark and quite oily only a few days post roast, have you pushed the roast too far?

    I've never had beans decaf or otherwise that was dark and oily but not over roasted - have you tried pulling back on the roast profile a bit?

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    Quote Originally Posted by askthecoffeeguy View Post
    if the beans are very dark and quite oily only a few days post roast, have you pushed the roast too far?
    It's my understanding that these beans are supposed to be quite dark. Andy's notes on beanbay say to roast by temp, not colour, because of this. Even when I've stopped the roast before second crack they are still far darker than other beans at this stage. Also hardly any chaff at all. The roasts I've stopped before second crack haven't been very good, my best results so far seem to be stopping pretty much right at the first hints of second crack. I'm pretty new to this though so happy to be corrected on anything

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    Rbn
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    Quote Originally Posted by Agrajag View Post
    Sorry not sure what you're asking? It is a fine grind but I am getting good extraction times. I've tried grinding it coarse enough that I don't get the clumps on the compak but then the extraction is just way too fast and I still get a sour underextracted taste.
    dumiya said it.

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    Life-long Learner DesigningByCoffee's Avatar
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    Quote Originally Posted by Agrajag View Post
    It's my understanding that these beans are supposed to be quite dark. Andy's notes on beanbay say to roast by temp, not colour, because of this. Even when I've stopped the roast before second crack they are still far darker than other beans at this stage. Also hardly any chaff at all. The roasts I've stopped before second crack haven't been very good, my best results so far seem to be stopping pretty much right at the first hints of second crack. I'm pretty new to this though so happy to be corrected on anything
    You've got that right. Even just before second crack these beans appear darker and get oily fairly quickly - but flavour wise they behave the same way as any other bean. So if you're getting a sour flavour try stretching out your time to first crack in increments to further develop the flavour without having to go darker at the tail end of the roast.
    And they are worth the effort - these beans knocked my socks off with flavour when I tried roasting them for the first time a few months a go! Way to go Andy!
    Cheers Matt
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