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Thread: Resting question?

  1. #1
    mwatt
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    Resting question?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Generally speaking, do you rest lighter or darker roasted coffees for longer? A scientific explanation of why would be appreciated ;) .

    Im sure Ive heard both, and have managed to get myself thoroughly confused ... ::)

    Cheers guys!

  2. #2
    Senior Member GregWormald's Avatar
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    Re: Resting question?

    I havent notice any difference between my roasts. I prefer ALL of them between 2 and 10 days. Before 2 days they taste a little like they have been mixed with soda water; after 10 days the tastes are starting to flatten out and the fresh fruity tastes are diminishing.
    Greg

  3. #3
    Senior Member Koffee_Kosmo's Avatar
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    Re: Resting question?

    I would also like the answer to this ??
    I just roasted some Nicaragua High Grown Bold to CS 8.5, just 2 days ago and was planing to start drinking it at about day 4 or 5
    By Gregs answer above, I am in the optimum start time.

  4. #4
    Senior Member Dennis's Avatar
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    Re: Resting question?

    Ill have a shot at answering, though Im sure there will be contrary views... ;)

    "Generally speaking"...Id rest lighter roasts longer than darker roasts.

    My reasoning (simplified format):
    Its a given that CO2 is produced as a process of roasting. In darker roasts, the cell walls are damaged more than in lighter roasts, and as a consequence more oils come to the surface. The damaged cell walls are also a better escape route for the CO2. And without CO2, coffee goes stale very quickly - hence the grind on demand rule.

    As an aside, darker roasted beans are also more brittle - you will notice they break much easier.

    If my reasoning is correct, then lighter roasted beans hold on to greater amounts of CO2 within their cell walls, particularly soon after roasting. Mix CO2 with pressurised water, eg. from an espresso machine, and you get carbonic acid...not very tasty. Resting for a bit longer allows the excess CO2 to be released and the chemical transformations to stabilise.

    I think this could be tested visually, by taking a dark and light roast of the same bean, then noting what happens as each goes through a grinder., one day, two days, etc. post roast.

    All said and done though, I am beginning to think that the term, "generally speaking" can be applied only to very few facets of coffee. Its really all about personal taste - if you prefer 2 day, or 20 day post-roast, dark or light roasted, then so be it!

    Just my thoughts. ;)


  5. #5
    Mal Dimal's Avatar
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    Re: Resting question?

    That sounds pretty close Dennis and reflects my own experience too.... :)

    I hate the use of "generalities" too as strict adherence to general guidelines probably leads to sustained levels of mediocrity. Youve just got to experiment and record all your observations of both roasting and cupping otherwise you run the risk of missing the "sweet spot" that really sets your palate alight..... 8-)

    Mal.

  6. #6
    mwatt
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    Re: Resting question?

    Thanks guys.

    Whilst I am quite happy to bend many the rules of coffee, I was after the generally speaking answer because I was hoping to avoid this thread getting bogged down and the question not being addressed ;) . I personally let my palate decide when somethings ready for me to drink, just couldnt remember what the generally speaking consensus was.

  7. #7
    Senior Member redzone121's Avatar
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    Re: Resting question?

    Yep personal taste must be the deciding factor for the individual.
    I now leave everything ,SOs and Blends for a minimum of 3 days, and make notes as the beans age. For some its 5 days and for others I can go as long as 10 days rest.
    Trial it and see what you like best but keep some notes its hard to think back a month or 2 later.

    CB

  8. #8
    Senior Member speleomike's Avatar
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    Re: Resting question?

    Hi all

    Dennis reasoned....
    > If my reasoning is correct, then lighter roasted beans hold on to greater
    > amounts of CO2 within their cell walls, particularly soon after roasting.
    > Mix CO2 with pressurised water, eg. from an espresso machine, and
    > you get carbonic acid...not very tasty.
    > Resting for a bit longer allows the excess CO2 to be released and
    > the chemical transformations to stabilise.

    I think your prob right about the porosity of the bean dropping as the roast is darker but Im doubtful about the CO2 being in solution in the form of carbonic acid. The gas has quite low solubility at 80-90C and I think all of the CO2 released will be in the crema as small gas bubbles i.e. mixed with the oils as part of the crema emulsion. I dont think you would even taste any acidity due to CO2 in solution. Carbonic acid is just so weak for any reasonable amount of CO2 in solution.
    Take cold soda water for instance (which has CO2 in solution), its not particularly acidic in taste.

    Of course Id love to have the book on Coffee Chemistry to be able to refer to that. But its 100s of dollars.

    Mike




  9. #9
    mwatt
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    Re: Resting question?

    Quote Originally Posted by speleomike link=1213084457/0#7 date=1213147522
    Hi all

    Of course Id love to have the book on Coffee Chemistry to be able to refer to that. But its 100s of dollars.

    Mike
    ;D My husband (chemistry teacher) has been ogling that one for aaages.

    I think you may be right about the crema bubbles- super fresh coffee does tend to have a very bubbly crema.
    But, it also does taste funny, not sure Id call it acidic, but it does taste underdeveloped ...

    Hmm, anyone out there able to run Coffee Chemistry 101?

  10. #10
    Senior Member speleomike's Avatar
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    Re: Resting question?

    Behmor Coffee Roaster
    Hi all
    One of the bigger factors that will occur over the first few hours and days is that the beans will adsorb water vapor from the atmosphere. This was driven out by the roasting process so the beans will "suck it back in again". (i.e. until the partial pressure of H2O in bean matches that of the atmosphere). I suspect that this water will enable some other chemical reactions to occur that result in changes in taste over the days. The sugars and oils for instance may well change.

    Mike



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