The Rationale behind Home Roasting Coffee

When I mention to others that I roast coffee at home, the inevitable response is, “Oh really?! Why?” It’s a legitimate question, especially for those who are either unfamiliar to the world of quality coffee, or see specialty coffee roasters all over the place. The reasons, and whether or not home roasting is right for you comes down to your own priorities. After nearly 9 years of home roasting coffee, here is my take, laid out in a way to help you weigh the pros and cons of home roasting.

A fresh batch of Sweet Maria’s “New Classic Espresso” blend roasted to Full-City+

The case for home roasting

Always fresh beans. High quality, freshly roasted coffee is the linchpin of a good cup of coffee. The very best espresso machine paired with a top quality grinder cannot make up for old beans. The prosumer espresso market makes it really easy to spend several thousand dollars on a nice espresso machine and quality grinder, yet the beans themselves are the reason for the equipment in the first place. Look at how many videos, forum posts and product reviews that debate the best tamping method, shower screens, or portafilter baskets. Yet, many times those discussions don’t even mention the roast, or are relatively dismissive of questioning the freshness of the beans.

Freshness of purchased beans simply can’t be trusted. Some roasters will pre-date their “roasted on” date after the true date of the roast, which works out well for them, and not so well for you. Other roasters have gone to a “best used by” date that is wildly optimistic. I’ve seen these dates on high quality beans set to 6 months or more, and enough questions exist with nitrogen filled coffee packing that should draw a healthy amount of suspicion. All of it is a practice that is unregulated, so good luck getting anything honest. They have little incentive to do so.

A note about Nitrogen filled coffee packing. Beans sealed in a nitrogen filled bag (not to be confused with nitrogen infused coffee) aim to reduce or eliminate exposure to oxygen: One enemy of coffee bean freshness. Assuming a perfect flushing and packaging process, it no doubt helps retain some freshness until opened, but it does not mean the beans are not changing, The degassing of carbon dioxide still occurs, as well as introducing a secondary shelf-life that is different than truly fresh beans.

Roasting at home also tunes your ability to spot and taste old beans quite easily. While dark beans (Usually Vienna and darker) can emit a bit of oil on the surface, fresh dark beans will hardly have any of this. Those beans found in the hoppers at the store, or your favorite commercial coffee chain that look like they’ve been dipped in motor oil. There is little incentive to provide fresh beans.

Almost zero waste. The short life span of roasted beans paired with the small batch sizes of home roasting mean always fresh beans with little waste. Roasted beans have a much shorter shelf-life than many would like to believe – something that becomes evident with working with the freshness of home roasting. You get to witness how beans lose their magic much more quickly than most realize. I’ve found that using them from the 2nd day through about the 7th day is great. The optimum flavor is really on the third day after the roast. This aligns quite nicely with the fact that I consume my 250g batch in about 5-6 days. Contrary to popular belief, using beans immediately after a roast aren’t terrible. They are simply a bit flavorless, and tend to be more difficult to pull good shots with because of the high amount of CO2 gasses emitted after the roast. I try to time my roasts so with about a 1-2 day supply still in the hopper so that the degassing is well underway, and the flavor of the beans is really ramping up. Meanwhile, unroasted green beans can live happily in your pantry for over a year. I usually buy a 20 pound bag that lasts me well over 6 months.

It doesn’t take that long. In my roaster, it is about 14 minutes of roast time for a 250g batch, not including the few minutes for the warm up. It’s simply not that big of a deal. Periodic vacuuming up chaff, and cleaning the roaster also falls in the “trivial” category.

Cost efficient. Home roasting can be a money saver. Premium espresso beans end up costing around $1.00 per 20g dose for a double espresso. Even after accounting for a 15% loss in weight after the roast, home roasted beans end up costing about 27 cents for that same 20g dose. With my existing rate of consumption (two espressos a day), pricing of beans, and roaster, it took me about 2 years to get to the break-even point. That was about 7 years ago. The math works even more in your favor if you have other coffee drinkers in the house, or are main-lining it into your bloodstream. The cost savings also has a psychological component to it. It allows you to experiment more freely, since the beans are just a fraction of the price of store purchased beans.

You learn about what roast levels, bean types and regions suite your taste. Purchasing green beans is easy and fast, with the ability to choose origin-specific beans, or blends. I purchase all of my beans from Sweet Marias. I have a few staples that I always go to (“New Classic Espresso” blend) but will often experiment with 1lb bags of region specific beans and other blends. Most importantly, you learn what you don’t like.

It can be enjoyable. If you are the type that is attracted to tinkering, or learning how things work, it can be an interesting exercise in chemistry, thermodynamics, and controlling variables. While I’ve let go some of my more extreme serotonin-inducing activities, I find working up a new roast a nice time-out from my day, with a great reward in the end.

The case for sticking with purchasing roasted beans

You don’t care. If you really don’t care, you probably should stop reading at this point, and continue doing what you’re doing.

You want a brain-dead method of getting your beans. A good roast can be the result of controlling a lot of variables. It is quite easy to get really consistent roasts from a decent home roaster, but it is not like throwing something in the microwave for 10 minutes. You have to babysit the roasting process, making adjustments throughout the roast. Some units have bean probe gauges paired with chamber temperature gauges and controllers to provide some level of automation, but for the simpler devices there are a lot of factors to consider that influence the outcome of the roast, making a time based recipe unrealistic.

Tip: If you want to increase the likelihood of purchasing fresh beans, go to your local espresso shop and buy some beans, but ask if they can scoop it out of the bag they are using for pulling espresso. This is usually pretty fresh, and a much better alternative to what they have sitting on the shelf.

You don’t want to spend the up-front cost for a roaster. A basic drum roaster that allows for full evacuation from the heat when the roast is complete (a must-have in my opinion) is not cheap. An electric-based Hottop drum roaster, capable of roasting 250g batches, will start you at $1,100. Other options that can roast 500g and even 1kg exist in the consumer market (actually blending over to the commercial sampler use case), but they increase in price, as they also tend to be powered by propane.

Can you get a more affordable roaster? Sure, there are a variety of different roasters out there, and some DIY concoctions exist using heat guns, or popcorn poppers. I’m not fond of toaster-oven style drum roasters because, among other things, you can’t evacuate the beans from the heat quickly enough (and manufacturers often warn against opening the doors because of the flash fires that can come from the chaff. Other alternatives tend to produce poor, inconsistent results. My position is, don’t waste your time on those low-end efforts. Roasting is much more than simply turning the beans brown.

You live in an apartment, and have no outdoor or well vented area to roast. The roasting process can produce a lot of smoke. In a surprise to many, the smoke has a bit of a burnt grass smell to it as opposed to freshly roasted coffee. It carries a combination of moisture and oil in aerosol form that latches onto paint, floors, carpet, sheetrock, etc. Roasting inside a residential home also presents a bit of a fire hazard. It is my position that if you are home roasting, it is best to do it out in your garage, on your deck, or just outside if possible. Some work up fancy vents so they can roast indoors. Take it out to your garage and call it good.

It seems like a hassle. I almost didn’t include this reason, only because I remember constantly running out of purchased beans, and running to the store to see if they had a fresh batch available, only to be sold out. An argument could be made that looking around for fresh beans can be just as much of a hassle as roasting them. But to each their own.

The wrap up

There you have it. The choice is yours. There is really no wrong answer, but if you dabble with your home coffee setup, you might want to think if this is the next upgrade for you. The payoff to me is quite simple. Higher quality coffee, for a fraction of the cost, with a tradeoff of a little up-front investment. To be honest, even if there was no cost savings, I believe I would still roast at home simply for the quality, consistency, and availability. The cost savings is icing on the cake. Good luck!

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