Roasting coffee is a constant work in progress. It has been for hundreds of years since the first roasting pan and open fire. Recently with the explosion of specialty coffee, 3rd wave operations and years of setting customer education higher, roasting is second only to origin in importance. Roasting for espresso takes a specific approach. Roasting for drip has another. And the reality is, at the specialty coffee level, Cold Brew Coffee Roasting has it’s own idiosyncrasies.


Why is Cold Brew Coffee Roasting so Different?

In reality, IT IS . . . and IT ISN’T.

The real truth is you can take just about any substance, soak it in water (the “Universal Solvent“) and over enough time extract gobs of interesting (and awful) things. Several factors affect this process: time, temperature, ph, pressure and much more

When it comes to coffee, extraction is the name of the game. Extracting all the good flavors possible, and limiting the extraction of what we do not want. Water itself has very little flavor. The only thing we can extract is the flavor compounds in the coffee bean that was (hopefully) roasted. The roasted coffee bean we hope to make delicious cold brew coffee from is a “substrate”. It is both our source for flavor, and our limitation.

Why We Roast

We roast coffee beans because green coffee beans taste like play-dough. And wet, old hay. And worse.

Roasting really does several things, and the deeper you go into researching it, the more complex it gets. And this article will never be able to cover a small amount of the reality let alone the myth out there. So lets just summarize the high points.

  1. Heat causes all sorts of on wonderful chemical changes that build and develop, then break down and redevelop more compounds. These don’t exist without this process.
  2. Heat also accentuates flavors locked in the bean itself, from the varietal, the agriculture, the processing, quality control, integrity in shipping and storage etc… It makes these flavors more accessible to extraction

So the goal is to apply heat and hope for the best . . . NOT! The real magic is figuring out how to roast for the clients project. This sounds a little overly simplified. However, we believe it to be more true than not. The endless debates about how to roast, what temperatures, how long, 1st crack, second crack, rate of rise and many many more terms don’t matter as much as WHAT THE PROJECT REQUIRES. The cult of roasting theory and the personal convictions of the roaster need to be used as a great starting place. They help us begin the process, but they don’t define the roasting process. They advise it.

What To Roast

This is the question for the specialty coffee ages. Again, our goal isn’t to figure this out and settle the millions of arguments put forth on the interwebs. The goal is to figure out WHAT THE CLIENT’S PROJECT REQUIRES. See the theme?

The factors that go into what to roast need to be considered in light of the end product. Every decision and choice about what to roast has to be rooted in the practical reality of it’s benefits for the clients end product. If not, the same key choices could undermine the clients end product. Don’t let the apparent simplicity of the idea take a back seat.

The number one criteria helps begin the selection process. And should be the deciding factor for the choice. Here are some basic principles, in somewhat of a priority list which might surprise the reader:

  • How consistent is the quantity of the supply going to be over the life of the product? Bet you didn’t see that coming . . .
  • How consistent and reliable is the quality of the supply going to be shipment to shipment, year to year, crop to crop?
  • How stable is the country of origin?
  • Are there parallel supplies of similar product in case of supply chain disruption?
  • How easy is the product to roast to spec?
  • How well does the bean provide the flavor compounds required for the end product?

Notice the weird order of priorities? They work in an almost opposite way most clients present their product. They will talk more often about flavor profiles and unique origins, how creative and unusual the product is. AND ALL THESE THINGS MAY BE TRUE! However the continuum of what to roast goes from hyper special, single origin, 3000 meter, shade grown, micro lot that had to be snuck out of country on a boat at a lunar eclipse at midnight all the way through reality to the other end where the product is nothing more than the most inconsistent, commodity based chunk of fibrous material waiting to be burned to oblivion.

How to Roast

Again, the torture! Air is best! Drum is best! Low and slow, fast and hot. Automated vs. fully manual. again, lets set aside the dogma and apply the same decision making parameters. WHAT IS THE BEST FOR THE CLIENTS PROJECT?.

Consistency, quality, and efficiency are the key determinants here. The best roast curve, the best time and temp, the best rate of rise… all of it works from the end product back. We want the maximum solubility (ability to extract essentially), getting the highest yield, with the best flavor profile.

Roasting for Cold Brew is a lot different than for Drip or Espresso. Because one of our main parameters (temperature) is pushed to such an extreme, the ability to extract is place upon the shoulders of the others (time mostly) to a much greater extent. We need to extract all the same  things, but with a lot less heat. Too much roast, and we lose the precious and unique compounds that make the product stand out. Too little, and we wont ever actually extract it. the reality is, the more developed the roast (either via time, or terminal temperature) the more soluble the flavors are. While there is a fixed point, it is a good rule of thumb. Darker roasts are more soluble. It is easy to over extract them in hot brewed applications, but in Cold Brew, the lack of heat works in our favor.

This is why so many product we taste are so dark tasting. The yields make it far more profitable because the single biggest cost is the roasted coffee. Plus it is easy to handle. Roasting so dark can be more forgiving, and lesser quality beans can be used because most of the origin flavors are lost when the roast is pushed farther along.

The real key is trial and error to get the right roast profile for COLD BREWING. The lack of extraction can often mean exaggerating the potential flavors to fit within he brewing parameters. This comes through serious testing, and repeating the process until it is proven right.

When to Roast

This topic hits on 2 very important topics: production planning and product quality.

Production Planning

In this scenario the planning means that no brewing can happen until ALL the coffee is roasted. You simply cannot really start the brewing cycle (typically the longest discrete process) until this step is done. So planning the roasting event needs to take into consideration when the brewing Master Date (see our Production Planning article linked above) is scheduled. Depending on batch size, if the roasting is a significant amount, it will take a few hours as well. Therefore the Due Date of the Roasting is the Master Date of the Brewing, and the Master Date of the Roasting is far enough in advance of the Brewing process to start. Sounds simple right?

2 Main problems with Raw Materials Planning

This article about small business manufacturing (in this case a cabinet maker, but the principle is the same), you see the 2 cardinal rules for managing inventory. To summarize:

#1 rule, don’t run out of inventory.
#2 rule, don’t have too much inventory

Green Coffee and Roasted Coffee are both essentially “Inventory”. However, the difference between plywood, aluminum, or other materials and Coffee is COFFEE IS PERISHABLE! As soon as you roast it, it accelerates the problem. You have a window of time to get the flavors extracted out into the water or you will lose them in the air. So the balance needs to be maintained between having roasted coffee available, but not letting it sit so long you lose the flavor intensity and extract able yumminess.

As a general rule… dont roast until the latest possible time, and hold roasted coffee for the shortest possible time.

Who to Roast

Who to roast is really about Where to roast and Why.

If you need unique control, have trouble sourcing or have other needs that would force you as the client to do the roasting, then the logistics puzzle is about shipping and timing of the roasted coffee only. You can save a bit of extra profit margin ont he most expensive Cost of Good, and have more influence on the logistics.

If you want to avoid the management, don’t have enough roasting capacity (or roasting at all), or the roasting skill set required for a more demanding product, outsourcing the roasting to a copacker is a better bet. Even if you are sourcing the green coffee yourself, drop shipping to the copacker can still have benefits for manufacturing flexibility and quality.

Summary

This topic just scratches the surface, but we hope it challenges the reader to think through these facets of the roasting process. There are a lot of considerations to review. This is one main reason why most beverage copackers wont even consider your cold brew coffee project. They cannot develop the resources in house for sourcing and roasting coffee. The ones that do roast and brew typically require you to use their cold brew (often an extract or concentrate). This means your options for flavor is extremely limited. By attempting to provide these services to our clients, we incur more moving parts, and more administrative overhead. However, the end product and the manufacturing process itself can be optimized in ways not possible before.

We hope to address several other key points in future articles such as the Brewing Process (Grinding and Brewing), Food Safety Requirements (at the current time there are federal guidelines coming shortly that will knock the industry on its head), Shelf Stability, Packaging, and Distribution. We believe helping prospective clients navigate the significant gulf between basic cold brew to real specialty co-packing will help set correct expectations, and position our customers for success.


Portola Coffee Lab and Cold Craft have extensive experience with sourcing specialty coffee, roasting development and leading edge brewing techniques. When we work with a potential partner for contracted manufacturing of cold brew coffee it is often surprising at how many factors need to be addressed to develop and scale up beverage manufacturing to high quality standards.

Contact Us if you want to know more about what we can do to help you with your cold brew manufacturing.

By | 2017-06-28T09:47:05-07:00 June 28th, 2017|Coffee, Copacking|