C.  Green Coffee Preparation

Coffee is ideally 10%-14% water weight.  In my work in Green Coffee in Colombia, we would strive to ship coffee as high as 16% so that it would arrive at the customer at that magic 14% moisture mark. 

During the roast process you can expect to lose up to 20% of the weight of the coffee due to moisture loss and burning of oils and other interior pergamino skins in the form of evaporation, smoke and chaff.

So for every pound of finished coffee that you require, add 3.2OZ or 20% extra coffee to your drum.  I found that this number works well for pulling the roast at second crack. So use this following table as a rough guide.  Every coffee is different so use this as only a rule of thumb.  If you roast well into 2nd crack, you will lose even more weight.  So, in general, the longer or darker you roast, the more and more coffee you will have to provide to complete the volume (12OZ or 16OZ) that you intend to sell.

To restate, a vienna roast will take more or less 1/3 more beans to make 1 pound of coffee as compared to a full city.   Plus, it will cost you more gas to get you to that point.  So, in order to reduce cost per pound keep your roast times shorter and less dark if you have the choice. 

While were on the subject of green loads, the 4, 6 and 8 pound drums are best rated for 4, 6, and 8 pounds of green coffee, not finished coffee.  That said, I have, in a pinch loaded 5, 7 and 9 pounds respectively into each of these drums and gotten decent, albeit slightly uneven roasts by adding a few degrees of temperature to my standard roast profile.  More on this later.

***PLEASE NOTE THAT THESE SHOULD BE CONSIDERED ROUGH RULES OF THUMB, EVERY GRILL, COFFEE, AND PERSON WILL ROAST DIFFERENTLY.  USE THESE NUMBERS AS A STARTING POINT AND LEARN WHAT BEST WORKS FOR YOU AND YOUR COFFEE.***

D.  Roaster Preparation

It is important to understand that each of the RK Drums (4, 6, and 8) will roast with approximately the same results at a given % volume for a given temperature.  So, a 4, 6 and 8 pound drum will roast the same at its 100% rated volume.  To clarify, a 4Lb Drum with 4Lbs of coffee at a given temperature will roast the same as a 8Lb drum with 8Lbs of coffee at the same temperature.

While each drum can roast more than its rated green volume, be aware that these tables show green loads in excess of the rated load, and can be done, but will need higher than normal temperature to accommodate the extra amount of beans.  Beware however, that your roast uniformity may suffer slightly.

The following table works for us with most coffees and should be used as a starting point. The numbers aren't exact, and you won't be exactly on these numbers no matter how hard you try, but you should be able to hit these numbers give or take 1 minute with these temperatures and get excellent coffee.

4LB DRUM

6LB DRUM

8LB DRUM

First thing you want to do is clean your grill if you haven't already, get the chaff and other material out of the bottom of the grill.  Take your green coffee load (I love the 5 gallon square buckets from the hardware store as you can use the corner as a pour spout to load the drum.)

Let's pre-heat the drum and the grill.  Light your burners and set to MAX temp.  Put the drum in the grill, close the lid and insert the clip.  Turn on the motor so the drum heats evenly and wait until the temperature rises close to your target temperature for the green load of your choosing.

When the temp gets close to the target temperature, turn off the motor and put on your protective glove on your unfavored hand (the hand that grabs the spit rod), open the lid, remove the drum and set the handle end on the ground and prop the coupler end up against the grill.

Close the lid to keep the heat in.

BE CAREFUL THIS THING IS SUPER HOT AND WILL BURN YOU INSTANTLY.  YES IT WILL LEAVE A SCAR!

E.  Coffee Loading

With your protected hand, pull the pin and open the drum.  I like to set the lid at a 45 degree angle and  use it as a bit of a funnel to pour the coffee into the drum. 

After you have all the coffee in, close the lid and insert the pin.  If the pin is real thick, just wedge it in tight, you don't actually have to have it fully inserted.  It makes it difficult to get out later.

Grab the rod by the coupler with your protected hand and grab the handle with the other hand and insert into the coupler and drop the handle side onto the bearing and close the lid on the grill and turn on the switch.

Continue on to Coffee Roasting