Developing a Roast Profile - Question about consistency and progression

[AndyP]

Hi all - I'm a new roaster, and I am starting a wholesale business with an Ambex YM5. I've got more research under my belt than actual time roasting, but I've been getting some pretty great results so far (at least for my standards). My favorite roast to date was a lighter Guatemala, but had slightly higher acidity than I wanted. I used the exact same gas settings, and instead of dropping the beans at about 12 min, I dropped a min later. I was going for a roast with slightly less acidity and slightly more body. Instead, I have a roast that is very very sour with almost no body. What gives? I warmed up the roaster for about an hour each time, and have a data logging system that has similar charge temp, equilibrium, first crack, and really the only difference is an extra minute and 15 degree higher drop temp. Same beans, same weight, as far as I can tell same everything. I'm really surprised at how bad it turned out! Any suggestions for the next roast?

 

[John P]

Not enough data to make an assessment.

This is why you need to have many hours of real world roasting reality before you can develop a theoretical profile. Developing a profile includes everything from roaster being used to batch size to cultivar of bean (specific bean density and other inherent characteristics) ambient temperature of the room, airflow, and lastly the result you are looking for and how to accomplish that.

Roast. Take notes. Adjust.
Repeat 10,000 times.

For consistency, quality, and an understanding of WHY and HOW those are achieved, there are no shortcuts.

 

[arnoldmoon]

I'm a newbie home roaster though, if everything was the same except drop temp and roast development time, might just have been a defect in a cup? maybe I would try extended roast time with same drop temp, lower ROR after or slightly before 1st crack?

Arnold

 

[Redswing]

Perhaps you could post more detailed notes of each roast. Ideal would be readings every 30 seconds of: gas setting, bean temp, drum temp, and whatever airflow control you have. Also the timing of first crack. Then we have something more concrete to go on.

 

[AndyP]

Ok - crisis averted. I may have measured it wrong for cupping or something - It was better the second time around.

 

[MillCityRoasters]

Ok - crisis averted. I may have measured it wrong for cupping or something - It was better the second time around.

I'm intimately familiar with the head scratching and frustration of a=b and b=c, but a≠c. This may be obvious, but it's worth noting that coffee sugars and acids have differing levels of solubility with sugars dissolving more quickly than acids. If only because of surface area and/or extraction time, a finer grind will often increase extraction where a coarser grind will diminish it. Cupping for roast profiles requires repeatability and predictability. Pick a charge and grind size and extraction method and protocol; then make all of that habit.

While you're at it, it often makes sense to think about your water quality too. It's kind of amazing how mineral content or lack thereof can affect extraction ratios.

All basic stuff and you probably have all of this figured out already. I'm just putting it out there to help the next guy.

 

[quantumbeancoffee]

Steve, Is there consensus that pure (0 ppm) H20 is worse for coffee extraction than mineral added H2O? I have heard and read this but have to admit that I brew everything with close to 0 ppm H2O(Reverse osmosis). I would rather have control over the H2O than no control. For instance if we say that 100 ppm is an ideal mineral content - my 100 ppm tap water in WV is very different than the 100 ppm tap water in Michigan. Michigan has a higher iron content and we have more Cal/Mag minerals than they do. I would have to think that the content of the minerals has to matter as much as the amount of minerals. If this is the case, what gives? Should we all just be using carbon filtered(Britta / Pur) tap water? Adding insult to injury I have also read that Pure 0 ppm H2O is recommended for espresso. So ideally we should have carbon filtered (w/ minerals) water for coffee and reverse osmosis (pure H2O) water for espresso?

 

[Musicphan]

Quantum... you do want to use 'mineralized' water vs. distilled. Here are some links to SCAA info.

Specialty Coffee Association of America
and more info..
Dissecting SCAA?s Water Quality Standard | The Specialty Coffee Chronicle

 

[MillCityRoasters]

Steve, Is there consensus that pure (0 ppm) H20 is worse for coffee extraction than mineral added H2O?

I understand there is a consensus for a minimum mineral content, but I don't remember what it is. Although city water in Minneapolis is pretty good, I use a bottled water service in the office for our espresso and cupping. Just down the street, Cafe Imports has a water filtration system worthy of the Starship Enterprise, but they cup thousands of coffees worth millions of dollars. We're just trying to come up with a reasonably okay roast profile for every coffee we offer.

I have spoken to our water service about filtration and conditioning and they have offered to do an analysis and provide recommendations. If you are curious, you might consider doing the same.

 

[7over]

... We're just trying to come up with a reasonably okay roast profile for every coffee we offer. ...

Steve, ... rather than using a distinct roast profile for each variety of coffee you offer, you want to be able to develop one single roast profile that will work well for any variety of coffee that you put in the roaster? Sort of a 'one profile to rule them all'?

 

[quantumbeancoffee]

I can't imagine that you would want to use the same profile for a Guatemalan as you would a Sumatran. I would think you would want to tweak the profile to the origin of coffee. There is no one profile to rule them all, in my experiance. There is however "commandments" like an always decreasing ROR or a development ratio.

 

[quantumbeancoffee]

Thanks for the reply , Steve. So, with the bottled water service you are using - is this RO water? Have you ever checked the ppm's? Seems like we might be cupping using the same water standards. I have no idea how to get water to the SCAA standards. Seems extremely difficult if not impossible. I can clean the water to close to 0 ppm. Or i can take water from the tap that has chlorine and other undesirable flavors. Either way it is not meeting the standards at all. I wonder if simply cleaning tap water with a carbon filter like the Berkey would suffice. Any thoughts on this? I will be serving coffee all summer at a farmers market and just want to make sure I am using the best water possible. I never imagined it being so difficult.

 

[John P]

quantumbeancoffee,

If you are using an RO system, then use a calcium carbonate re-mineralization filter to put back minerality in the water, OR you can simply give the water chemistry you want to your local water system professionals and let them figure out the best way to get it there.

Also for general TDS there are digital meters for $25 to over $200 that can give you that reading easily and efficiently.

I would look for a system that is easily adjustable (if need be) and easily serviceable. Much depends on your volume and ROI for the system. If you go for a more expensive ($2500+) system, try not to get locked into proprietary filters. Just like roasting, there are thousands of ways to get to the right result. Find the one that is best for your needs.

 

[MillCityRoasters]

Steve, ... rather than using a distinct roast profile for each variety of coffee you offer, you want to be able to develop one single roast profile that will work well for any variety of coffee that you put in the roaster? Sort of a 'one profile to rule them all'?

Dave Borton runs our green selections. He's cupping recommended new crop from Cafe Imports, Royal, and Olam and breaking bags up for our guys. He's passing on cupping notes and roast profiles to help them get started. We shoot for SCAA 87+ quality coffee. With coffee that good, it's actually kind of hard to not get a reasonably good roast, but we're still learning too. That means cupping and lot's of it. So much so, I actually considered investing in spittoons today. :coffee1:



That said, as far a "one roast to rule them all" goes, if you like aromatics, we think Scott Rao's diminishing ROR technique comes pretty close

 

[MillCityRoasters]

Thanks for the reply , Steve. So, with the bottled water service you are using - is this RO water? Have you ever checked the ppm's? Seems like we might be cupping using the same water standards. I have no idea how to get water to the SCAA standards. Seems extremely difficult if not impossible. I can clean the water to close to 0 ppm. Or i can take water from the tap that has chlorine and other undesirable flavors. Either way it is not meeting the standards at all. I wonder if simply cleaning tap water with a carbon filter like the Berkey would suffice. Any thoughts on this? I will be serving coffee all summer at a farmers market and just want to make sure I am using the best water possible. I never imagined it being so difficult.

When I first set up our water subscription, I read their analysis and was satisfied it was close enough for me.

Personally, I'd try filtered tap water vs RO a couple of times to see what happens. If it's a big difference, you might want to change something. If not, leave well enough alone? I imagine you'll find you'll get a slight increase in dissolved sugars, but that may just be me drinking the kool-aid.

SCAA level cupping as a gauge of crop quality is much more rigorous than the farmers market. I pay $60 per month for water. At our level, that's about the most I can wrap my head around. I know guys that would shudder at the way I prepare coffee, but I don't think most of them have ever had a date. - just sayin', for perspective.