Announcement

Collapse
No announcement yet.

Importance of rapid cooling for light roasts?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Importance of rapid cooling for light roasts?

    I have a question for our roasting experts:

    I understand well that for dark roasts cooling the beans quickly is important to stop the roast at the desired level.

    My question is whether it is so important for a light roast? I am testing out a new roaster ( :)- it has the option to remove the beans for rapid cooling (manual) or leave them in for an automated slow cooling cycle. This cycle is quite slow- taking ten minutes- and leaving the beans warm to the touch...

    If one is only aiming for a light to medium roast is there any reason why a slow cool-down would be less preferable to a fast one? Assuming that both achieve the same colour/roast result by finishing the slow cooled roast a little earlier?


  • #2
    Re: Importance of rapid cooling for light roasts?

    I am certainly no roasting expert, but my research has led me to believe that fast cooling (within 4 minutes to room temp.) is critical in getting the best out of roasts - regardless of light or dark.

    I definitely noticed the improvement with my Behmor when I started pulling the beans as soon as I hit the cooling cycle, and chuck them in a colander in front of a large fan to force cool them. I get them down to room temp in about 3 minutes.

    Comment


    • #3
      Re: Importance of rapid cooling for light roasts?

      Heres my take...

      If you took a green bean and heated it "warm to the touch" ie 40C would it roast?
      Nup.
      So I doubt that anything is going on in a bean if its <60C or more, even coming back down to 150C after taking it to 200C+ I doubt much will change. You could test that in the kitchen oven pretty easily to confirm it.

      Back to the question though, a "light roast" is still going to be post first crack and 200C odd. That will keep roasting during the cooling cycle until you get the bean under 150C.

      So... as long as you can take 50C+ out of the bean quickly then your roast should stop roughly where you stopped.

      Getting the post roast temp down to 100C not much will be happening as the water is well gone and none of the other chemical changes will take place. Similar to stalling a roast, stuff stops!

      So the experiment needs to be...
      roast your light roast, at the end of the roast drop half into an external cooling tray and the other half into a pre-heated oven at 100C for another 10 minutes before cooling.

      Try them and see if there is a difference
      8-)

      Comment


      • #4
        Re: Importance of rapid cooling for light roasts?

        Reading andys post, Im not so sure that nothing would be happening at 100c. I just set me thinking about baking meringues and sous vide cooking -plenty of chemical reactions continue at lower temps. Well worth some further testing I think, not that Im a roasting expert...

        Comment


        • #5
          Re: Importance of rapid cooling for light roasts?

          Thanks for the detailed response Andy. I will do a few oven tests and see if I can discern any difference in the cup.

          Still interested to hear of any other theories about slow cooled light roasts?

          Comment


          • #6
            Re: Importance of rapid cooling for light roasts?

            Originally posted by 434B454D4F555549454D260 link=1306315775/3#3 date=1306372529
            plenty of chemical reactions continue at lower temps
            I think that would depend on what is being heated.

            Comment


            • #7
              Re: Importance of rapid cooling for light roasts?

              Originally posted by 0F332E353F3E293C343F5B0 link=1306315775/5#5 date=1306381282
              Originally posted by 434B454D4F555549454D260 link=1306315775/3#3 date=1306372529
              plenty of chemical reactions continue at lower temps
              I think that would depend on what is being heated.
              True.

              Question: why is it recommended to store roasted coffee in a cool place?

              Comment


              • #8
                Re: Importance of rapid cooling for light roasts?

                it is true that things will degrade faster at a higher temperature- over time- but would that play out with an extra 8 minutes or so at a higher temp?

                I guess the only way to tell is to do some comparison testing.

                Comment


                • #9
                  Re: Importance of rapid cooling for light roasts?

                  My understanding is that it is some of the reactions going on with the sugars that are affected by rate of cooling, what actual temp they stop at I am not sure, but the guideline I came across a number of times in my research was less than 5 mins to room temp.

                  I am guessing its not the actual temp thats critical, rather pulling as much heat out as quickly as possible and room temp is an easy concept for people to work towards.

                  I suppose the only other question is whether there is any potential to cool coffee too quickly and prevent some particular post roast chemistry from completing.

                  Comment


                  • #10
                    Re: Importance of rapid cooling for light roasts?

                    Originally posted by 6C646A62607A7A666A62090 link=1306315775/6#6 date=1306382529
                    Question: why is it recommended to store roasted coffee in a cool place?
                    To reduce the effects of oxidisation over the course of a couple of weeks consumption
                    Higher temperatures act as a catalyst to oxygen

                    Comment


                    • #11
                      Re: Importance of rapid cooling for light roasts?

                      Originally posted by 2B30392F2C21580 link=1306315775/9#9 date=1306454126

                      To reduce the effects of oxidisation over the course of a couple of weeks consumption
                      Higher temperatures act as a catalyst to oxygen

                      Which supports my contention that some chemical reactions DO continue in the beans at temperatures well below roasting temps.

                      I agree with galumays post, interesting thought.

                      So much to learn, so little time.

                      Itll be a while before I move on to cooling profiles, only just getting started on roasting profiles. Will be interested to read more on this though

                      Comment


                      • #12
                        Re: Importance of rapid cooling for light roasts?

                        Originally posted by 2028262E2C36362A262E450 link=1306315775/10#10 date=1306455671
                        Which supports my contention that some chemical reactions DO continue in the beans at temperatures well below roasting temps.
                        Of course "some chemical reactions" occur at temperatures well below roasting temp.
                        Pretty hard to stop nature wanting to decay things

                        Comment


                        • #13
                          Re: Importance of rapid cooling for light roasts?

                          Would placing the beans in the fridge to cool rapidly be too much of a shock to the beans? For quicker cooling, do most people dump the beans into a room temperature pan and spread the beans out to cool quickly? Or do you use a fan to air cool them?

                          Comment


                          • #14
                            Re: Importance of rapid cooling for light roasts?

                            Theres no need to place the beans in the fridge to cool them. Most people use a colander/sieve and fan type arrangement for quick cooling as seen/linked to in this thread: http://coffeesnobs.com.au/YaBB.pl?num=1274757802


                            Java "Blowin in the wind" phile
                            Toys! I must have new toys!!!

                            Comment


                            • #15
                              Re: Importance of rapid cooling for light roasts?

                              I cool my beans out of my popper first by tossing them in a metal colander.

                              Then I spread them onto a baking tray that acts as a heat sink. In warm weather I use 2 or 3 trays, the heavier the better. The beans are in a single layer.

                              In a couple of cases I have been able to see and pick out feral stones.

                              I usually leave the beans on the tray for about an hour before bagging up.

                              Barry

                              Comment

                              Working...
                              X