coffee roasting

Home Roasting and Lean Manufacturing


On my recent tour of commercial roasters I had fun looking at their manufacturing and warehousing processes.  I like warehousing and manufacturing.  I don’t work in that industry, but I like all the processes: cool conveyor belts and forklifts and all sorts of activity.  Whats not to love?  And when its a coffee warehouse, roaster, and manufacturer just about everything I find cool is located in one place.

The roasters i toured were operating on purpose.  I’m not sure if they are formally Lean or Six Sigma or some other ‘plan’, but they are operating with thought and purpose behind their activities.  Here are some points of Lean, commercial roasting, and how the points may impact home roasting:

  • Chaff is recyclable organic material.  When I sweep my chaff into the lawn, I’m not being lazy.  I’m recycling.
  • Lean puts a lot of emphasis on ergonomics.  How ergonomic is your roasting set up and can you improve it?
  • Blend strategy impacts inventory.  You should chose your blend strategy based on flavor, but if you blend before roasting you won’t need to maintain blend stock.
    • I’m not blending but it was neat to observe that commercial operators approach blending with different strategies.
  • Consistancy.  Lean and Six Sigma want to measure and eliminate varation.  Roasters measure and track varations in their roast.  I wonder if I need to measure and track my finished products.
    • I’ve tried to use a roast log but I didn’t really know how I was going to use it.  I wonder if I can switch from a roasters log to a tasters type of log.  Track the finished level of roast and the finished taste.
  • Green storage is interesting.  Even if you are buying container loads, greens are transported and stored in 150 lb jute bags.  It seems that there are a lot of non-value added steps in this process.
  • Disaster plans: Both roasters had contigencies for disasters.  My backup plan for beans is to run down to starbucks  🙂




Recently I was lucky enough to do a coffee cupping with a master roaster for a really large commercial roaster.  It was a really cool experience.  I tried once or twice to do cuppings at home but its not as easy as it sounds if you don’t know what you are doing.

We did a finished product tasting and a traditional coffee cupping.


We tasted 5 different blends/roasts.  The neat part is two of the sampels were the same blend, roasted to different levels.  I was aware of the importance of roast in an intellectual level but I haven’t actually roasted the same beans to different levels (at least not on purpose).  The roast level was only a little different but the taste was totally different.

The challenge with home roasting is quantity.  How do I roast and taste to different roast levels of the same bean?  I only order a few pounds of each bean and I don’t want to have tons of fresh roast going stale.

But its for science.  Maybe on my next sweetmarias order I’ll order only one coffee instead of an assortment and try and set up a tasting.  You all are invited  🙂

Traditional Cupping:

After the tasting, the rest of the people I was with left and I had the cool opportunity to do a cupping with the Master Roaster by myself.  The first thing I learned was that spitting into a spittoon is harder than I thought.

The spittoon goes between your legs.  I put it off to my side at first and it was just too awkward to be sitting on the spinning chairs and trying to lean over and hit the bucket.  I really didn’t want to spit all over the floor.

The Roast Master hadn’t planned on doing a cupping with me, if he did he would have selected different beans.  The beans that we tasted were the beans that his team cupped in the morning.

As we went around the table tasting, all I could taste was coffee.  I just smiled and tried to taste but it all just tasted like coffee.  I was relieved when he told me that this was hard since all these beans tasted the same.  Shew.  I did taste a difference in the 5th sample, it was brighter than the other 4.

At Home:

As for the practicality of doing this type of cupping from Home roasting, I’m not sure.

I’m not really going to reject a shipment from Sweet Maria’s?  I think I’d be better off doing a tasting.  Roast two different beans or the same bean to different levels and brew up 2 cups in the morning.  That way when I drink 2 cups of coffee in the morning, I’m not over-indulging, I’m tasting for science!

Cooling your Beans!

For years I cooled my beans using a colander and a fan.  It worked, but there were a few flaws with what I was doing.  Among other things, I want to get more ‘professional’ in my roasting.  My cooling method was fine to show a friend, but I’d be embarrassed to show a theoretical ‘paying customer’ what I was doing.  I was hunched over on the ground trying to keep my colander balanced on the fan while using a wooden spoon to stir the beans a bit. 

I came across a remarkably easy to make contraption that works better than I expected.  You take a shop vac and connect the hose to a container.  In the lid of the container you cut a hole just big enough for a colander.  I made mine with the box that the shop vac came in and I used duct tape to hold everything in place.  As I perfect my procedure I’ll switch to a plastic container, but cardboard and duct tape are easy to experiment with (and cheaper).

To use the contraption, you want to suck air into the shop vac (as opposed to blowing air out).  In just a couple of minutes I am able to bring the beans down to the ambient temperature.  To remove chaff, reverse airflow for a bit until there is nothing else to blow away.

Now that I have a device that can consistently cool the beans, I can experiment with taste.  During one of my future roasts, I’ll pull out a cup of beans before cooling and then compare those beans with the beans that were properly cooled.


Coffee Roasting Improvements

Here is an intellectual exercise that can improve your home coffee roasting skills.  Work out what it would take for you to sell your coffee commercially.  If you are like me, you know that your home roast is better than what you can buy in your local market.  What do you need to do to sell it?

After a particularly frustrating day at work I figured I’d chuck it all and just sell beans.  I know, pie in the sky, tilting at windmills kind of thinking, but it did give me a project to play with for a bit.  I went through the marketing 4Ps to figure out what steps I needed to take.   Price, Promotion, and Place can be skipped for this discussion, but when I seriously looked at ‘Product’ I saw weaknesses in my roasting that I needed to correct if I want to create pro-quality beans.

I grew up ‘dog bowl roasting’.  I enjoyed the method, but it was a chore.  It took forever, it was boring, and it produced low volume.   My attitude of roasting became just get ‘er done.  I roasted by ‘feel’ and gradually became less and less precise in my roasting.  I upgraded to a BBQ drum roaster in an attempt to improve quality and increase volume.   However, my attitude never changed from my dog days.

If I truly want to roast good coffee, I need to convert much of the art of the roast into a repeatable science.  I increased my roast volume not to improve quality but to reduce the ‘chore’ of roasting.  I was roasting 2-3 pounds in a single roast.  The actual roast was good, but we only go through about a pound a week.  And I wasn’t actively working to improve the processes.

To do:

  • Reduce batch size –> fresher beans and more frequent roasting to improve technique.
  • Improve bean cooling technique
  • Improve roasting hardware
  • Improve palette
  • Figure out how roasting profiles improve bean flavor

Coffee Concentrate

Coffee Concentrate

The ‘concept’ of coffee concentrate seemingly will fit nicely in my coffee consumption schedule and my roasting schedule. This was supposed to be a simple and quick quest, do a little google kung-fu and then I’d have concentrate. Alas its taken me months of ardous research to develop my concentrate. Or maybe its taken me months because of other reasons …

I’ve mentioned before that now that I have a drum roaster, I can roast more beans than I could possibly drink. One way to increase the ‘volume’ of home roasting is to figure out a way to drink my home-roast at work. I’ve tried to brew at work but thats a hassle and its a little more pretentsious than I like to be. Plus I usually drink coffee because I want to get away from my office – so I make a trip to Starbucks with my laptop. I got this vision of developping a concentrate based drink that I could make and then go to a park to work.

For my roasting schedule, we flip back and forth between traditional french press coffee and espresso. I love espresso but there just seems to be a lot more romance in a micro-lot of beans from Sweet Maria’s that I don’t find in an espresso blend. So I roast ‘coffee’ for about a month or so and then roast ‘espresso’ for the next month. I figure at the end of my coffee cycle I could take the ‘coffee roast’ and turn it into concentrate. Then I’d sorta have both coffee and espresso available.

‘Intellectually’ the idea was compelling. However I had no idea what coffee concentrate was. My google Kung-fu got me several recipes which basically went along the lines of making french press coffee with cold water and then wait 24 hours. The problem with recipes that include “and wait 24 hours” is that 24 hours later I’m doing some other project. And I don’t have a huge inventory of roasted beans, I try to keep everything fresh. I can’t just grind away beans or I’ll be drinking Tea in the morning (bleah). My ability to run repeated experiments causes this simple experiment to take several months because of these roadblocks.

Experiment #1: My first concentrate recipe I found was about a cup of beans + 4 cups of water. Which is just about my normal french press recipe (should have been my first sign). I made the concoction and stuck it in my fridge. The next day I plunged it and tried some — Yum, water with a slight coffee taste!

Experiment #2: I identified the problem, I stuck the coffee in the fridge – the recipe called for setting out at room tempeture. Repeated the experiment, plunged it. Yum, water with a slight coffee taste!

Experiment #3: I knew I was doing something wrong, beans + water + some function = concentrate. I came across a recipe that gave more detailed instructions (probabably because I actually read them this time). 1 ounce of beans to 4 ounces of water. I whipped out my kitchen scale. Measuring by weight indicated I was way way low on beans – I was only using 1/3 of the beans I needed. I reran the experiment with 1/4 pound of beans and 2 cups of water. After waiting the perscribed 24 hours I plunged. A drinkable product came out! I made myself a cup and went to work. I came home and wanted to make a second drink to validate my findings. Unfortunately my wife spilled my container – it was all gone. If you ask her, I left the bottle out and didn’t put the lid on properly — so don’t ask her.

Experiment #4: 1/2 pound of beans:4 cups water. Wow, thats a lot of beans, the grinds fill up half of my large press, I wasn’t sure the water would fit. But now I have a decent amount of concentrate to experiment with.

I still have much experimentation to do on this and it will be slower going than I thought. There is about a week or two of time between each experiment. But I think I have a framework now to work with. I need to figure out the right ratio to “rehydrate” my concentrate and what the best way to serve this product. It seems to be a product that needs sugar, like a sweet ice coffee, but maybe thats because I was craving sugar at the time.

Heat Guns

Heat Guns

In my years of dog bowl roasting I’ve gone through 4 different heat guns.  Bottom line, in case you don’t read everything is:

#1: You want a professional quality gun in order to get consistent high heat.

#2, Light weight will make roasting more enjoyable.

1 Wagner HT1000?*

Pro: Available in-store, cheap

Con: Low Power

Wagner HT 1000

I believe my first gun was a Wagner HT1000, although mine was black (sorry Wagner if it wasn’t you).  Whatever model it was, the big-boxes carried 2-3 types of heat guns.  The “cheap one”, a “digital one”, and maybe a third similar gun with another feature.  The best thing I can say about the in-store guns is they are cheap.  As I was on a tight budget this was a compelling feature.   The gun “worked” for roasting but it wasn’t very powerful.  You’ll be happier if you skip these low power guns and get a “real” gun.

Wagner HT1000

2. Makita HG 1100

Pro: Light weight, works good

Con: Melts

 Makita HG 1100 

I purchased a Makita HG 1100 in August 2005 from Amazon. I loved the increased power and was finally able to get the performance that I wanted.  After about 2 years the blue plastic near the output began to melt.  Maybe I was resting the gun while I was roasting and eventually distorted the gun?  Whatever the case, smoking and burning plastics is probably a sign that it was time to get a new gun.

Makita HG1100

3 Wagner HT 775

Pro: Won’t melt, works good for awhile, good customer service

Con: Heavy, didn’t last long

 Wagner HT 775

Perhaps plastic wasn’t the right material for a heat gun? So I found a Wagner that was all metal.

However, After 7 months the gun stopped working.  I spoke to customer service and it turns out that roasting is not the intended use for the gun and therefore not necessarily covered under the warranty.  Roasting requires the gun to be used for 20+ minutes at a time, multiple times a week, The normal use of the gun isn’t nearly as intense.  So I went on bought another gun.  And as the way things work, shortly after I bought my new gun, Wagner shipped me a brand new gun!

Wagner HT775

4  Milwaukee 8975

Pro: Light weight, works good, lasts forever

Cons: None

 Milwaukee 8975 

My 4th gun, purchased in 2008, was a Milwaukee.  Yep, went back to plastic.  I couldnt’ find another metel one that looked good and Milwaukee seemed like a good brand.  I didn’t realize it at the time, but the all metel Wagner weighed a ton!  When you are holding the gun for 20 minutes with one arm and stirring with the other, lighter weight is a nice feature.  This gun is still in great shape – even though I leave it outside.

Milwaukee 8975



Drum roasting challenges


One of the challenges I’m working on with my drum roaster is accurately predicting the roast level. I spent years doing dog bowl roasting. Turns out I was doing my roast evaluation based on a visual inspection. I could hear the crack, but I really was watching the beans.

With my drum roaster, the magic is done in secret behind the stainless steel lid of the grill. I’ve lost my ability to do a visual evaluation. Even when I peak, the drum itself obscures the view of the beans. It can be frustrating — I’m experimenting with larger batch sizes. I hate tossing $20 worth of beans in the trash because I messed up.

With the larger batch size, it seems that the right amount if heat is critical. I tried to raise the average heat to 550 and I ended up with some beans blacker than coal and most beans barely roasted to light cinnamon shade. When I carefully monitored heat and kept it at 500, I was able to get a consistent roast.

The other ‘fun’ thing that occurred now that I have to rely more on sound is my last roast came out much darker than ever before. Usually the beans come out as a deep dark brown, but this time they came out black.

This roast level makes an awesome strong Capp. The espresso now cuts straight through the milk and lets you taste the espresso. Yum. So much so that people that prefer “expresso” drinks didn’t really like the taste — they had to add a lot more sugar.



Drum roasting

Drum Roasting:

I used my dog bowl setup for years. However this method limits the volume of beans you can roast in one session. And it isn’t very fun to roast during the winter months. I previously read about BBQ roasting, but at the time I didn’t want to build or invest in the necessary equipment. But after a particularly crummy day I decided that it was time to take my roasting to the next level.

I used my google-Kung-fu and I found a drum roaster for my grill that was inexpensive (

My first few months with this roaster were very disappointing. The setup of the equipment was unreliable and worse, the drum lid wouldn’t seal properly allowing my beans to escape into the grill. These problem were largely self-inflicted.

I couldn’t get the spit to work right, it would fall off the motor or the handle would come lose. I couldn’t get the drum off the fire hot spit at the end of the roasting session. I was so familiar with dog bowl roasting that I could do everything with my eyes closed. I was excited about having a new toy to play with so I was rushing through all of the set up. This problem had a simple solution: slow down. I now progress through these steps methodically and have much better results.

I was having some success doing 1-2 cups of beans. But when I put in 3-4 cups into the drum, the beans would force their way out of the drum during the roasting cycle. My expensive CoE beans from would catch fire in the grill. Not good. Fortunately, Len from was quick to respond to my frustrated emails. He suggested that I make a slight modification to the lid, which I of course ignored. However, after burning another few batches of expensive beans I repented and got out my drill.

With the modification to the drum in place and a steady methodical approach, I’m now having a consistently good product. And I am looking forward to a more comfortable winter roasting season.



Dog bowl roasting

Dog bowl roasting

The method of roasting I recommend to my friends is dog bowl roasting. I produce (usually) good coffee in about 15-20 minutes. Since you are right in the action, you see how the roasting process works. Best of all this is a cheap entry into roasting as you already have most of the equipment needed in your kitchen and garage.

You need a heat gun capable of reaching 400-500 degrees, a stainless steel bowl (traditionalist will want to use a dog bowl), a long wooden spoon (a plastic spoon will melt and a metal spoon will get too hot), a way to dissipate heat (I use a fan and colander), and 1-2 cups of beans.

Pour the beans into the bowl. Turn the gun on and hold it 1/2 to 1 inch from the beans. Then stir and stir and stir….. I have a friend that stirs with the nose of his heat gun though I’ve never attempted that so your mileage may very. Be careful not to burn the beans. If you hold the heat directly on a bean for too long it will burn.

Depending on the power of your gun, the type of beans, and the quantity you are roasting, roasting will take 15-25 minutes. If you make a dark roast, your beans will progress through two “cracks”. First crack is usually easy to identify -because it’s first. :-). Second crack can be a bit trickier. It occurs closely behind first crack and sometimes even occurs while some beans are still in first. First crack tends to be more “snappy” like a finger snap or a dry twig snap. Second crack is softer, more like wrapping paper crackling and a lot of smoke. After a few roasts you’ll have a good understanding of the different cracks.

The final step is cooling. Dump the beans in the colander (careful as the bowl and beans will be very hot). Set the fan upside down with the air flow going up. Put the colander over the fan and stir.

If you don’t have a fan, spread the roasted beans on a large cookie sheet and stir. You need to dissipate the heat or the beans will “bake”.