Oily beans and grind fineness

Postby geeek204 on Thu Dec 22, 2011 3:42 am

Setup: Crossland CC1, Breville Smart Grinder (newer model that does not need shim upgrade)

Bought some dark roast espresso beans from the local roaster; fresh roasted 4 days ago and very oily. Went to dial in the grind on the Breville and had nothing but problems! Grinder down to its finest setting and dosing anywhere from 18 - 20 grams (CC1 does not like overdosing) and getting 15 second extractions every time. Even tried up-dosing until I could barely lock in the portafilter and the extraction time did not change.

Went back to roaster and picked up a medium-dark roused (just short of 2nd crack) roasted on the same day as the previous beans, little to no oil on these guys. Put some in the grinder and immediately choked the machine. Had to dial it back 4 notches and resumed my usual 18g dose for a 27 second extraction.

Just wondering, has anyone had this major of a difference between roasts? Could it also be the oily beans messing with the extraction? Had something similar to this happen in the past but figured it was a fluke, but it happening again made me reconsider. Any tips?
geeek204
 
Posts: 24
Joined: Dec 22, 2011
Location: Southern California

Postby mitch236 on Thu Dec 22, 2011 1:34 pm

Oily beans can cause problems in grind consistency. My take is that the beans stick to each other slowing the feeding into the throat of the grinder and removing the weight from the bean column that the grinder sees. This would cause the grinds to be inconsistent and coarser. Moving to less oily beans now the grinder is properly weighted by the bean column and is grinding more consistently. Also, if the grinder is new, there will be variations until the burrs are seasoned.
mitch236
 
Posts: 1195
Joined: Jul 21, 2010
Location: Florida
www.compasscoffeeroasting.com: coffee is culinary
www.compasscoffeeroasting.com: coffee is culinary

Postby adan0327 on Mon Dec 26, 2011 12:41 am

changing different grind settings is completely normal when changing beans.

Factors that affect this that I can think of right now:
size of bean
when it was roasted
oily or not

example: when im dining peaples dailt its 9.4 on my super jolly and when I drink peoples liberation i have to set it to 9.25 to get the same yeild of apporximately 27grams.

IMO don't buy dark roasts. There are a lot of good coffees that are medium roasts.
adan0327
 
Posts: 32
Joined: Sep 11, 2011
Location: Toronto, Canada...I love maple syrup and riding polar bears, yes

Postby cannonfodder on Mon Dec 26, 2011 1:01 am

A dark roast will often take a finer grind. It simply needs a finer grind than your grinder can produce.
Dave Stephens
User avatar
cannonfodder
Team HB
 
Posts: 7724
Joined: May 23, 2005
Location: Downingtown PA

Postby Randy G. on Mon Dec 26, 2011 8:54 am

I normally roast my own coffee, and never dark, and never with oil showing. Recently got a batch of dark, oily beans from a commercial roaster and had to go ten marks finer on my Kony to get a decent extraction time
Espresso! My Espresso!
http://www.EspressoMyEspresso.com
User avatar
Randy G.
 
Posts: 3127
Joined: May 12, 2007
Location: Yankee Hill, CA