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How Vacuums Prevent Coffee Staleness

How Vacuums Prevent Coffee Staling

By | Coffee

Coffee storage and freshness are influenced by a confusing mix of variables that greatly affect how long your beans stay tasty. We’re a big fan of vacuums as a means of extending your coffee’s shelf life (if you couldn’t tell from our new Atmos Vacuum Canister). Here’s a handy guide on coffee freshness that explains why vacuum canisters are so effective at keeping your coffee fresher, longer.

Why is oxygen so bad for coffee beans?
Oxygen is bad for coffee, snacks, or pretty much any perishable item because it makes things stale through a process called oxidation. To set the stage, we define “staleness” as the loss of desirable flavors and aroma, and/or the creation of undesirable flavors and aroma. When oxygen comes in contact with a molecule, it removes an electron from the molecule. This is called oxidation. The molecule that loses an electron becomes unstable and reactive, which then results in the loss of flavor or creation of an undesirable flavor.

For coffee beans, oxygen negatively affects VOCs (volatile organic compounds). VOCs are chemical byproducts of roasting that evaporate quickly. They are generally considered good because they contribute to aroma.³ When oxygen comes in contact with VOCs, they become unstable and result in coffee losing its aroma.

Oxygen also affects lipids, which are the coffee oils in the bean. Oxidation turns lipids into peroxide which contributes to rancid taste notes.7

Fellow Atmos Vacuum Canister for Coffee
What’s a vacuum container and how does it help with oxidation?
First off, let’s define what a vacuum is. A vacuum is a closed system in which pressure is less than atmospheric. In order for this to happen, you need a constant amount of space (i.e. a rigid container) where air particles are removed.

There’s a lot of airtight containers/bags out there that get rid of some air, but these aren’t necessarily a true vacuum. An easy way to tell if you don’t have a vacuum container is if your container shrinks (i.e. is it a bag or does it have a lid that collapses into the container). If your container shrinks, it is not a vacuum and will not decrease the pressure below atmospheric.

But why is pressure so important?
Oxidation speed (the rate of oxidation) depends on pressure.¹A reaction occurs when two molecules collide. If there are more molecules in a smaller area, the chances of collision increases and the reaction happens faster.

Air is a mixture of nitrogen, CO2, and oxygen. For the oxidation reaction, we care only about the pressure of oxygen – or the partial pressure. The partial pressure of oxygen is the fraction of oxygen in the air, times the total pressure of the air. The partial pressure of oxygen can be changed by changing the fraction of oxygen in air (i.e. nitrogen flushing) or changing the total pressure of the air (i.e. vacuum chamber).

Fraction of Oxygen in Air x Total Pressure Air = Partial Pressure of Oxygen

Here’s an example of this equation for calculating the partial pressure of oxygen:

—————-

What is the partial pressure of oxygen in a) atmosphere and b) a half vacuum?

Fraction of O2 in air = .2095

Total pressure of atmospheric air = 101.325kPa

Total pressure in half vacuum air = 50.66 kPa

Fraction O2 x Total Pressure = O2 partial pressure

.2095 O2 x 101.325 kPa = 21.23 kPa

.2095 O2 x 50.66 kPa = 10.61 kPa

Therefore, O2 partial pressure a) 21.23 kPa and b) 10.61kPa  

——————–

From calculating the partial pressure of oxygen in a half vacuum, we can conclude the oxidation rate at full pressure is twice as fast as the oxidation rate at half pressure, which is the environment Atmos creates. Although oxidation and freshness have a very strong correlation, because there are other factors at play like degassing, the relationship is not linear. If it was, we could say Atmos slows the oxidation rate by 2x, and therefore extends coffee’s shelf life by 100%.

We landed on the conclusion that Atmos extends coffee’s shelf life up to 50% due to the many variables that go into how fast a specific bean goes stale (origin, roast, how many times you open your canister, degassing, etc.)

What happens to the degassing rate of coffee in a vacuum?
If vacuum chambers affect gas on the molecular level, then it’s important to consider how vacuums affect coffee degassing. When coffee is roasted, gases form inside the bean. After roasting, gases (mostly carbon dioxide) start seeping out. When coffee is a few days old and very fresh, a bulk of the carbon dioxide formed leaves your beans. Because vacuums create a pressure gradient, CO2 degassing will occur quicker than at full atmospheric pressure. When we first started designing a vacuum canister, we wanted to make sure this didn’t harm the flavor profile of coffee or its ability to stay fresher longer.

Our conclusion was twofold. First, 40% of CO2 in coffee escapes within the first 24 hours. Most of the degassing happens very quickly in the first few days after roasting.² By the time you get your coffee, it has probably already done a bulk of its degassing so vacuum canister effects on CO2 are minimal.

If you do get your coffee extremely fresh (1-3 days off roast), a vacuum canister will degas coffee quicker, which in theory, is a negative outcome because degassing too quickly can also lead to the loss of volatile organic compounds (VOCs) that create aroma. However, as we talked about earlier, it turns out those same VOCs, along with lipids, are the molecules most affected by oxidation. Oxidation is the primary reason for coffee staling.5 When assessing the impact of fast degassing versus oxidation, it is clear oxidation has such an overwhelming impact on coffee’s flavor that protecting your beans from oxidation is significantly more impactful than preventing a small increase in the degassing rate.

Since this is a sealed environment, will this mean there is a buildup of CO2?
We’ve received a few questions about CO2 buildup in Atmos compared to in a bag with a standard one-way valve. Commercial coffee bean bags with CO2 degassing valves are designed to relieve CO2 pressure buildup and prevent bag rupture, not to necessarily keep coffee fresher for longer. In a vacuum chamber, the pressure is low enough that CO2 buildup is not a concern. CO2 in the air around the beans is non-reactive and will not affect the flavor of the coffee. CO2 does, however, affect your coffee’s flavor once you start brewing, so make sure to bloom your bed of grounds before brewing!4

Can I put Atmos in the freezer to store coffee?

You can freeze Atmos but it’s not the best use of the product. Since coffee beans should be frozen in individual servings as to not refreeze and freeze beans continuously, Atmos doesn’t make the most sense. Atmos is intended to hold multiple servings, so it would be a waste of space in your freezer to put only one serving of beans inside. Placing Atmos in the freezer will also eventually reduce the life-span of the vacuum seal.

Atmos Vacuum Canister Coffee Storage
Additional questions?
We hope this answers your questions on vacuums, coffee freshness, and Atmos Vacuum Canister! As always, we will continue posting our research as we receive questions from customers and the coffee curious. If you have additional questions or comments reach out to hello@fellowproducts.com, so we can continue serving up the latest and greatest coffee information!


REFERENCES

1.) Cengel, Y. A., & Boles, M. A. (2012). Thermodynamics An Engineering Approach. McGraw-Hill Science Engineering.

2.) Illy, A., & Viani, R. (2005). Espresso coffee: The science of quality. Amsterdam: Elsevier Academic Press.

3.) Rao, S. (2014). The coffee roasters companion. Canada: Scott Rao.

4.) Raper, A. Is Your Coffee Too Fresh? Retrieved from https://clivecoffee.com/blogs/learn/is-your-coffee-too-fresh.

5.) Sage, E. (2017). What is the Shelf Life of Roasted Coffee? A Literature Review on Coffee Staling. Retrieved from http://www.scanews.coffee/2012/02/15/what-is-the-shelf-life-of-roasted-coffee-a-literature-review-on-coffee-staling.

6.) Schenker, S. (2000). Investigations on the hot air roasting of coffee beans. Zürich: ETH Zürich.

7.) Smith JP, Daifas DP, El-Khoury W, Koukoutsis J & El-Khoury A. (2004). Shelf Life and Safety Concerns of Bakery Products: A Review. Critical Reviews in Food Science and Nutrition 44(1):19-55.

Jun Shan Yin Zhen | China’s 10 Most Famous Teas

By | Tea

The rolling hills of China’s southern Yunnan Province have been identified as the birthplace of tea. Anthropologists say here is “where humans figured out that eating tea leaves or brewing a cup could be pleasant.”¹ As the top tea producing country in the world (followed by India and Kenya), the options of Chinese teas are seemingly endless. If you’re new to this vast world of tea and overwhelmed by the available selection, we recommend working your way through the list known as “China’s 10 Most Famous Teas.”

1) Xi Hu Long Jing (Green Tea)
2) Dong Ting Bi Luo Chun (Green Tea)
3) Huang Shan Mao Feng (Green Tea)
4) Jun Shan Yin Zhen (Yellow Tea)
5) Qimen Hong Cha (Black Tea)
6) Wu Yi Da Hong (Wulong/Oolong Tea)
7) Lu An Gua Pian (Green Tea)
8) Anxi Tie Guan Yin (Wulong/Oolong Tea)
9) Tai Ping Hou Kui (Green Tea)
10) Xin Yang Mao Jian (Green Tea)

Each of these famous teas is recognized by its characteristic leaf shape and size, appearance, and taste. In total, there are six green teas, two wulong teas, one black tea, and one yellow. We’ll be highlighting a tea from each of these categories, but first, we’re starting with yellow tea. China is currently the only major producer of yellow teas, and even in China, it is a very rare type. In Tony Gebely’s book Tea: A User’s Guide, “Yellow tea is defined by a unique processing step where small batches of tea leaves are wrapped in cloth bundles after fixing, allowing them to yellow. While wrapped, the leaves turn from green to yellow-green as chlorophylls are broken down. Vegetal flavors mellow and subside, and the tea leaves partially oxidize.”

Chinas 10 Most Famous TeasThe only yellow tea to make the cut for China’s Ten Most Famous Teas is Jun Shan Yin Zhen (or Junshan Silver Needle). This incredibly rare yellow tea originated on Junshan Island in Hunan Province’s Dongting Lake, the second largest freshwater lake in China. Besides this tea, Dongting Lake is famous in Chinese culture as the place of origin of dragon boat racing and is home to the endangered Finless Porpoise.

This is was what the Finless Porpoise looks like in case you were curious. He’s a bonafide day brightener. (Photo Credit: www.china.org.cn)

Jun Shan Yin Zhen is made up purely of hand-sorted buds that are fixed (heated), wrapped in small bundles, and dried. Unlike most black, oolong, and pu’er teas, “yellow teas are not usually rolled or shaped in any way. The original plucking standard is preserved.”² Junshan Island’s soil and climate give the tea a sweet fruit aroma and light sugarcane taste. “The tea’s small growing area and the skill required to make it result in only a small quantity of authentic Jun Shan Yin Zhen produced each year.”³

We used our Raven Stovetop Kettle to brew the Jun Shan Yin Zhen. With Raven’s integrated tea filter, you can heat and steep in the same vessel saving time and cleanup. Since tea is even more sensitive to water temperature than coffee, Raven’s steep-range thermometer helps you dial-in the correct degree point.

Jun Shan Yin Zhen Yellow Tea Chinas 10 Most Famous TeasTea Characteristics

  • Brew Color: Light Yellow
  • Flavor Profile: Light sugarcane
  • Aroma: Sweet fruit

Brew Instructions

  • Add 1-1.5 tsp for every 8 oz of water
  • Heat water to 190°F
  • Steep tea in Raven’s filter for 2 minutes
  • Enjoy!

If you’re interested in brewing Jun Shan Yin Zhen at home, Tea Drunk and Seven Cups both have great options. Happy steeping, friends!


Sources:

  1. Fuller, Thomas (2008-04-21). “A Tea From the Jungle Enriches a Placid Village”. The New York Times. New York. p. A8.
  2. Gebely, Tony (2026). Tea: A User’s Guide. p. 70
  3. Seven Cups Fine Chinese Tea. “Jun Shan Yin Zhen Yellow Team”. Tucson, Arizona.
Fellow Prismo Affogato Recipe How-To

Prismo “Affauxgato” Recipe

By | Coffee

An affogato is the perfect summer pick-me-up or a delicious way to impress dinner party guests with minimal effort. Usually, a traditional affogato takes the form of a scoop of vanilla gelato or ice cream drowned in a hot shot of espresso. But if you’re not the proud owner of an expensive espresso machine, how are you going to pick yourself up in the summer or make a fancy dessert for your great aunt?

Have no fear. Prismo is here! Swooping in with another one of his superpowers to save the day, our mighty AeroPress® Coffee Maker attachment is an affogato-making superstar. Well, we like to call it an “affauxgato” since Prismo technically makes espresso-style shots.

Our sales manager Jake Mix invented this recipe one afternoon in the Playground, and the team has been hooked ever since. Classic vanilla ice cream is the go-to, but our dairy-free Fellows used Ben & Jerry’s Non-Dairy Chunky Monkey from the corner store and the results were off the charts.

But enough chit-chat, time to check out the how-to for Jake’s famous Prismo “Affauxgato” recipe!

WHAT YOU’LL NEED:
Prismo
AeroPress® Coffee Maker
Vanilla ice cream or gelato
20 grams of finely ground coffee
50 grams of 212°F water

STEP-BY-STEP RECIPE:

1. Dose out 20 grams of whole bean coffee. If you happen to own a Stagg Pour-Over Dripper, you can also load the beans to the “single dot” measurement inside of its ratio aid instead. No scale required!
Fellow Prismo Affogato Recipe How-To
2. Heat water in your pour-over kettle to 212°F and grind beans on a very fine setting. We did ours at 1.5 on the EK43.

Fellow Prismo Affogato Recipe How-To3. Twist Prismo onto the bottom of your AeroPress® Coffee Maker and dump in the grinds.
Fellow Prismo Affogato Recipe How-To

4. Add 50 grams of the 212°F water into your AeroPress® Coffee Maker and stir vigorously for 15 seconds. Let sit for one minute.
Fellow Prismo Affogato Recipe How-To5. During the one minute brew time, add one heaping scoop of vanilla ice cream to your cup or mug.

Fellow Prismo Affogato Recipe How-To7. After one minute of brew time, plunge the AeroPress® Coffee Maker over the ice cream.
Fellow Prismo Affogato Recipe How-To8. And enjoy!
Fellow Prismo Affogato Recipe How-To

Do you have any go-to Prismo recipes? Send us a message via Instagram or Twitter. We love seeing your Prismo creations!

Wade Preston’s Winning US Brewers Cup Qualifier Prismo Recipe

By | Coffee

Wade Preston of Prevail Coffee Roasters walked away with the first place prize at this year’s New Orleans Brewers Cup Qualifier. He went on to compete at the 2018 US Brewers Cup Championships in April. Here’s the kicker…he used Prismo as his coffee brewing apparatus of choice. This is the first time Prismo has been used in competition, and we couldn’t be more excited that our little AeroPress® Coffee Maker attachment is making waves on a national stage.

Wade Preston Coffee Champs Prismo RecipeWade shared his winning Prismo recipe with the Fellow team a few weeks ago, and we’ve tested it out in the Playground many times since. What’s our verdict? Yeah, it’s really stinking good!

Give it a try for yourself and let us know what you think!

WADE’S PRISMO RECIPE

  1. Place an AeroPress® Coffee Maker paper filter on top of the Prismo metal filter.
    Grind 18 grams of coffee very coarse. Bottoming out an EK grinder with stock burr spacing is probably about right.
  2. Sift grinds with a 600 micron screen like the Kruve.
  3. Load your grinds into the AeroPress® Coffee Maker.
  4. Pour a 50 gram pre-infusion with 145°F water. (Yes, you read that right!)
  5. Stir gently to ensure all grinds are saturated.
  6. Let pre-infusion immerse for 3 minutes. (Yep, three minutes as in 180 seconds!)
  7. Fill to 205 grams with 208°F water.
  8. Stir 5 revolutions with AeroPress® Coffee Maker paddle.
  9. Let immerse for 2 minutes and 30 seconds.
  10. Stir 5 revolutions and plunge, steadily for 30 seconds until you hear the vacuum seal break.

It will create a cup that will need to “settle.” If you taste it right away, it’ll be good, but the body won’t be there. After it has set for about 1-2 minutes, the body will ramp up. At about 130°F, it is a huge, creamy, and almost chewy. The cup will also be crazy sweet.

Wade Preston Brewers Cup Prismo Recipe

WADE’S THEORY
At the particle level of coffee extraction there are two types of solubles: surface solubles and inner cell solubles.  Surface solubles extract very easily. They also give coffee its sweetness. Think of how sweet and syrupy cold brew is…that’s because it is pretty much 100% surface erosion extraction. Heat and turbulence are required for inner cell extraction which creates coffee’s complexity (bitterness, acidity, etc). The idea with the above recipe is that you can isolate the surface erosion extraction by doing the low temp pre-infusion. This will delicately extract the surface solubles. Then, you can safely extract the inner cell solubles without fear of over-extracting the surface solubles. That’s the gist of it anyways!

Follow Wade on Instagram for more great coffee content: @wadepreston


Prismo is a pressure actuated valve designed to be used with the AeroPress® Coffee Maker. This attachment allows for a buildup of pressure to create espresso-style coffee and creates a no-drip seal for a full immersion brew. The reusable 70-micron etched filter stops sludge in its tracks and eliminates the need for paper filters.  The valve’s small aperture also fits directly over an espresso shot glass.

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Fellow Team Booth at the Specialty Coffee Expo 2018

Specialty Coffee Expo 2018 Recap

By | Coffee

Our favorite week of the year has come and gone, and all we’re left with is sweet, sweet memories and caffeine withdrawal after consuming 20 cups a day for three days straight. The Specialty Coffee Expo, or SCA for short, was held in Seattle again this year and the entire Fellow squad made the trip. Our highlights outside of the convention hall include a team banana relay race around a high school track, an insane dinner spread cooked by our friends from Fellow Taiwan, and hula hoops mixed with inflatable unicorns at the La Marzocco party.

Our highlights inside the convention hall could be a never-ending list, but we managed to narrow it down to our three favorites! Read More

How To Make Cold Brew With Prismo

By | Uncategorized

Some like it hot. And some like it cold. Luckily, Prismo covers both ends of the coffee temperature spectrum. Our mightly little AeroPress® Coffee Maker attachment can “pull” espresso-style shots and bust out delicious full-immersion brews, but it’s also an easy-to-use cold brewing champ!

Experiment with the Fellow Team’s go-to cold brew recipe below and wake up to a strong, chilled concentrate in the morning!

THE RECIPE

  1. 35 grams of coarsely ground coffee (light or dark roast)
  2. 130 grams water, room temperature
  3. 12-24 hours steep time

STEP X STEP

  1. Grind 35 grams of coffee as coarse as possible á la French Press style. Place the AeroPress® Coffee Maker plunger 1/4th plunged into the brewing vessel. Flip the brewing vessel so the chamber is facing up.
  2. Add 35 grams of coffee and 130 grams of room temperature water to the AeroPress® Coffee Maker.
  3. Stir for 20 seconds to ensure the bed of grinds is fully saturated.
  4. Twist Prismo onto the top of the AeroPress® Coffee Maker.
  5. Store in fridge for 12-24 hours. Because Prismo is airtight, you can store your cold brew inverted or right side up!
  6. After 12-24 hours, press down on the AeroPress® Coffee Maker plunger. The added pressure of Prismo’s pressure actuated valve will agitate and squeeze out all of that cold brew sweetness. This recipe is a cold brew concentrate, so make sure to add extra water or milk to taste!

Psst…Prismo can also brew tea!

Brew Like A Champion with Stagg EKG and EKG+

By | Coffee

Want to brew like the best of them? Break out your pour-over gear and follow along as Dylan Siemens of Onyx Coffee Lab and the 2017 US Brewers Cup Champion, walks you step-by-step through his techniques and pour-over recipe for one.

Stagg EKG and Stagg [X] Pour-Over Dripper get the star treatment in our latest video!

Dylan’s Featured Recipe
22g of coffee to 350g of water | 200°F water | Medium grind
@0:00 – 50g bloom
@0:30 – Pour to 200g
@1:20 – Pour to 350g
Drain by 2:45

How To Brew Old Coffee

By | Coffee

You bought a solid bag of coffee some sunny Saturday afternoon with the intention of brewing before work. As the following weeks unraveled, you neglected that beautiful bag of beans. Next thing you know, your coffee is stale. You don’t want to waste those precious beans but don’t want a cup that tastes like old cigarettes. What to do?

There’s hope! Depending on how old the coffee is, you can actually salvage it into a pretty decent cup with some simple tricks.

Read More