Rob Hoos Interview on Coffee Roasting With Roast Rebels

Discuss roast levels and profiles for espresso, equipment for roasting coffee.

#1: Post by minus1psi »

The forum software suggested starting a new thread rather than extending the existing one in a new direction.
pcofftenyo wrote:(from post #61 of a different thread.) Thanks for summarizing the Hoos interview. And thanks to both of you posting up your curves.
@pcofftenyo, Please regard those dozen lines of notes as teaser content!

The interview is information-dense and about an hour long. The snippets from my notes would have been in the first 5 minutes. The interview is the best information I have encountered so far -- even if that is unique to me, as in it just hit 'right' for what I needed to hear, I encourage anyone with an interest in roasting to watch it. Hoos has a soft place in his heart for home roaster. He might have said so in that interview. It comes through either way.

(By the way, I morphed the information in the interview to fit my roasting situation and have no recollection of discussion about dropping the roasts at a specific temperature, although I have seen unrelated videos where that is implied. It may be in that interview or it may not.)

I stopped taking notes somewhere in the middle, maybe 2/3 of the way through. The discussion had moved to selecting commercial roasting machines - which is just not relevant to my needs.

After this the discussion moved to roast defects, some objective (scorching, tipping, facing, chipping), some subjective (baking, over-roasting, under-roasting, over-developed, under-developed). My notes there are closer to transcriptions. IIRC after roast defects the discussion moved to selecting a roasting machine.

Here is a little more teaser content, please be prepared my typos, non-sequiturs, awkward and/or incomplete wording.
How to roast better coffee - an interview with Rob Hoos 

In response to question: What are the most important decision for roaster
Hoos cites and details research shared by Morten Münchow (researcher in Copenhagen)
	• biggest drivers of flavor from roaster
		#1	roast color
		#2	development time
		#3	time to 1C
		- biggest change you can make is to change the final color of the roasted coffee
		- whole bean color is primarily about temperature exposure
		- average color of ground beans is affected by length of development time
			◊ short development time -> lighter color (whole and ground bean)
			◊ longer development time decreases the difference between whole and ground
			bean colors. It brings ground bean color closer to whole bean color.
		- development time plays a huge role in flavor of coffee
			◊ +/- 10 seconds for consistency
		- increasing time pre-1C increases body and complexity (caramel, nuts, etc) 
		- increasing time to 1C decreases clarity and floral notes	
	• green coffee has a huge influence on final result
		- "can't polish a turd"
			◊ 80pt green coffee is hard to roast such that it reaches 80pt result
			  with very little room for error
			◊ 90pt green coffee can be roasted imperfectly and still taste good
		- higher altitude coffees tend to be more acidic
		- lower altitude coffee tend to be less acidic
		- processing overrides a lot, giant generalizations are
			◊ natural process overrides cultivar and terroir
			◊ naturals tend to be fruit-forward, earthy, chocolate-y, more body
			◊ washed process coffees tend to be citric and malic, more floral, lower body
			◊ honey-processed coffee tend to be middle-ground between natural and washed
	• differences in roasting natural process vs washed coffee
		- natural process
			◊ shorter development time 1:15 to 1:30
			◊ roast naturals a little bit lighter than washed
			◊ Joe Morroco says "pretend natural process are already a little bit roasted"
		- washed process
			◊ longer development time 1:30 to 2:00
			◊ shorter development time on washed coffee tends toward vegetal flavors
	• generally do not roast below 11% weight loss

Roasting for espresso
	• espresso extracts a lot of acidity
	• espresso tends toward under-extraction. 	
	• stretch the roast to get more or at least different maillard by-products
		- stretch the time to 1C
	• roast for more complexity and more body
	• use longer development time to neutralize some acidity; 
	• roasting darker can help bring balance
	• low-end weight loss for espresso: 13%-14%
	• high end weight loss: sky is the limit, depending on personal taste

Developing even color in a roast
	• stretching development time helps even inside-outside color evenness

Comparing roasts by weight loss
	more than .5% roast to roast delta weight loss means changes in flavor
	.25% weight loss is goal for roast-to-roast consistentcy
	11%-13%	 weight loss = light roast
	13%-16%	 weight loss = medium roast
	16%-18%	 weight loss = dark roast
	18%-22%	 weight loss = extra dark roast

Bean Density
	• how to measure bean density...
		equipment needed
			50ml graduated cylinder
			gram scale that reads to 1/100g 
			fill graduated cylinder with 40ml water
			add beans to get to 50ml
			result: know how many grams it takes for 10ml
			multiply that number by 100 to get g/l
	• low density coffee has increased risk of roast defects if fast roast
	• high density coffee - roast as fast or slow as you want
	• low density:	1120 g/l <- soft coffee, be gentle while roasting
	• high density:	1160 to 1200 g/l <- unlikely to push it so far as to cause tipping

Moisture Content and Moisture Meters
	• Good resellers will know the moisture content of the beans they sell. Otherwise
	it is necessary to buy specialized equipment to measure moisture content. Low-end
	meters are around $300.
	• beans with moisture above 11.5% will spoil faster than beans with lower moisture 
	content. As a guess roast that coffee w/in 6 month
	• Higher moisture levels require energy to roast.  Beans with 11% water require 
	more energy to roast than beans with 10% water content.

How to roast better coffee - an interview with Rob Hoos
Channel: Coffee Roasting With Roast Rebels (55:07)
Interviewer: Ingo Albrecht

Team HB

#2: Post by mpdeem »

Thanks for providing the link as well as some notes. I just ordered Rob's book on roasting so will report back when it arrives.

It would be interesting to have a series on roasters -both rebels and conventional -the only criteria is a sincere desire to produce good roasts. This could include comercial roasters and consultants. For example would be neat to compare roast profiles and 'roast philosphy' of say roasters who use primarily one level-type of roasting with minimal variation versus others who roast at a wide varety of levels. Could have a variety of roastering styles ad 'eras' represented... from Klatch, Black & White, Panther, Blue Bottle, Intellegesia, Marhsall Hance...and so forth. Not a competition or debate but rather simple a collection of roasting approaches and styles.
★ Helpful


#3: Post by dyno »

Very cool. Thank you for taking those notes.

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#4: Post by LBIespresso »

Just watched it a second time. Thanks for posting this. I really liked it. Funny thing is I skipped looking at your notes until I came back to watch a second time. Very good summary!

The comment about naturals was the thing that stood out most to me.
LMWDP #580


#5: Post by Milligan »

Thanks for the link. I read Rob Hoos "Modulating the Flavor of Coffee" essay and didn't care for the presentation or the study method compared to Rao's polished literature. I haven't revisited his information since so this seems like a good way to dip the toe back in.