Posted Sat Oct 26, 2013, 9:16am Subject: Re: Roasted espresso bean storage
Len -- I haven't used it, but I'd be skeptical of any company that makes this statement:
The Friis Freshness Valve vents away flavor destroying CO2 gas
I think we have established that CO2, if anything, has a protective quality -- eliminating O2 which is the oxidizing compound.
I use a vacuum canister, the Bean Vac canister, which is now discontinued. I do not think it makes a great difference in how I use it - opening it every day. It might help if I were keeping it sealed for a while, but I defer to the tried and true freezer storage for longer-term storage.
Dana Leighton - Espresso hack and CoffeeGeek moderator
I am not sure of what you speak, Dana. CO2 is "generated" in the roasting process and MUST be allowed to escape (so called "de-gassing") for the beans to be useable. Using beans just after roasting produces a cup that is undrinkable...and it is said to be "gassy".
Can you point me to any discussion about the protective benefits of CO2.
Maybe I need to clarify my use of the words "Expresso Bean Storage". I have never kept beans for much more than 10 days post roast and usualy use them within 1 week of roast. So, my use of the term "storage" refers to how they are held from roast date through use ~ 1 week later. I am NOT "storing" beans as some of you are for some weeks. So, my use of the Friis or other storage comatiner will be for use from the immediate de-gassing through consumption. Right now, Len's Espresso Blends roasts once or (rarely) twice per week. I bring home (usually) 1 pound of #5 + 1/2 pound of FTO, sometimes more and these are gone within ~ 1 week.
What I currently do is leave the beans in their wire sealed, kraft paper bag for a day or so out of raost and then transfer them into airtight containers.
Do you guys think the Friis will suit a short storage time? Or is there some other product that you would recommend. Whatever it is, it will have to have a one-way air valve to allow de-gassing.
Although I have not use the Friis storage volt, I think it is good for storing roasted beans. Actually once the beans are roasted, oxygen start to stale. We need to keep it in a close container so that oxygen cannot get inside. Also, you can use one way valve bags to store roasted beans. Again, any airtight close container can be used for storing.
Did you know...? Dark roast coffees actually have less caffeine than lighter roasts due to the fact that the process of roasting burns off caffeine. www.coffeeloversmag.com/theMagazine
Think about beer. If you tap a keg of beer with one of those hand-pump taps that pushes air (and oxygen in the air) into the keg so it will flow through an outlet tube into your cup, the keg of beer will go stale in about 2 days...its pretty nasty. So how do bars keep a keg of beer on tap for weeks at a time (assuming they dont sell it all)? Carbon dioxide of course. CO2 from a pressurized tank, instead of air from your pumping-tap, is pushed into the keg, generates pressure, and the beer comes out. Unlike oxygen, CO2 does not oxidize beer...or coffee. On the chemical level, the C in CO2 is unable to accept any more friends because all of its arms are used up by the two O's. Oxygen, or O2 on the other hand, has some free arms that don't mind shaking hands with stuff in your beverage of choice/beans.
This is a long way of saying that CO2 will not harm, but rather preserve your beans. The one way CO2 vents on bags of coffee one buys are somewhat of a marketing thing. Coffee smells wonderful and we are far more likely to buy a bag if we can push that CO2 out and smell all of the good stuff.
The benefit of the beanvac is that it sucks out the air that enters the container after you open it. Not all vacuum pumps are created equal, and the little pump on the beanvac leaves behind a whole lot of air. It doesn't take much oxygen to oxidize coffee, we're talking about atoms here so think small. Thus, I have a beanvac and don't use it anymore because I saw no difference over a ball-jar.
Using a vacuum sealed bag and re-vacuuming after each time you open it would be the best way to keep air out...but I dont' know many people that are going to do this. Yes, the bag will start to "puff" once the beans let off their co2, but that co2 isn't doing anything. If you are going to store beans on a relative budget, this is the way to go.
Wine fanatics are so worried about oxidation (rightfully so), that devices have been developed that inject nitrogen (N2) into the bottle. Nitrogen is considered inert and is even less likely to affect anything (there is actually zero reaction). Aragon would work too. Who wants to make us a device like this for coffee?
Not to dismiss all those vacuum contain products, but a vacuum pump that will actually suck out a worthwhile amount of air costs a few hundred dollars. The $25 range for most of these contains should show you that the pumps aren't worth buying. Here are some that are!
The one way CO2 vents on bags of coffee one buys are somewhat of a marketing thing. Coffee smells wonderful and we are far more likely to buy a bag if we can push that CO2 out and smell all of the good stuff.
A marketing thing!!! Coffee beans just out of the roaster are NOT useable because they need to "bleed" off the CO2 "generated" in roasting. The bags with one-way air valve alow the CO2 to bleed off while NOT allowing O2 in - if properly sealed. It is possible to simply put the beans in a wire tied ("standard") bag and the CO2 will bleed off - but air will also oxidize the beans as the bags are not sealed...they are merely closed.
Len's Espresso Blends, as well as nearly all other "high end" roasters, ships in heat sealed bags with one-way air valve because it alows the beans to arrive at the buyer's house de-gassed and ready to use.
I pretty much always get my week's worth of beans on my roasting day each week and have occasionally put them in sealed bags with one-way valve - AND THEY TASTE BETTER when they are first used and I have always wondered about this. I bring my coffee home in standard tin-tied bags as these only cost ~$0.18 each vs. ~$0.55 each for the bags with one-way air valves. My bag price is NOT based on the measly quantities used by Len's Espresso Blends but is passed through from my roaster who roasts thousands of pounds per week and buys his bags in huge quantities.
I swore by mason jars for years now and I still do. I usually would roast with the lids loose allowing the C02 to escape then after 18-24hrs I'd seal them up. Recently I've switched to ziplocked, valved, foil bags because mason jars if left our are vulnerable to sunlight. I've noticed a lot more aroma is produced if the air is allowed to escape for a longer period of time without having new air age the beans. They are cheap and re usable. I use a china pencil to mark the bags so I can erase and reuse. They go for about $0.50-$1.00 depending on where you buy them. I have a box of about 400. :p
I store for 1 month.
Consumer storage containers are too expensive I think. You can do the same with the above for under $1.00.
Dear Whitcoatsyndrom, I take issue with your second premise, but I know how unpleasant it is for someone to disagree with me in public, so I will say: "I agree with you that all the little pump jars remove an insignificant amount of oxygen".
There are a number of amateur vacuum projects, including coffee evacuation, on the web. One kitchen experimenter on this forum used a automotive vacuum gauge on his manual pump to document the effective vacuum and was able to pull a vacuum that measured 20 in/Hg on the gauge. I said to him:
Evacuating flexible bags would seem to be the most efficient use of the vacuum technique. But it has the drawback in that a considerable amount of oxygen remains among the spaces between the beans. Even though there is less oxygen, the concentration (percent) oxygen and the partial pressure of oxygen, which both partly determine the chemical rate of spoilage, remain the same. Flexible bag evacuation was ideally designed for preservation of solids such as cuts of meat. Trapped air, such as in a bag of beans, defeats the efficiency by a considerable factor. Placing the bags in a freezer is the only mechanism that significantly retards spoilage, since temperature also determines the rate of spoilage. Evacuating a rigid container such as a canning jar provides some increased benefit. It is my understanding that for any engineering discussion of effective vacuum techniques there is a significant difference between absolute pressure of the evacuated system and gauge pressure. But, please, lets accept the kitchen experiment in the helpful spirit that it was intended. The gauge pressure reading of 20 in/Hg (uncalibrated but let us assume it is accurate) translates to a decrease of pressure by a factor of 507 mmHg, or 66%. Any true engineers: please correct me if I am wrong. This means we are evacuating 2/3 of the gas in the jar by using the universal gas law, PV=nRT. The amount of oxygen is proportionally decreased by 2/3. If we assume that the freezer decreases the bean temperature by 15 degrees Celcius, the rate of staling has been reduced to 1/3 by evacuation and 1/2.8 by freezing (Arrhenius equation), so staling should proceed at 12% the 'shelf-life' rate (100 x ((1/3) x (1/2.8)%). Regarding evacuation, Michael Sivetz writes, "A 28.5 in vacuum leaves 1 percent oxygen in the can, and this is about the maximum possible if deterioration is not to be apparent the first month" (Sivetz and Desrosier, Coffee Technology, 1979, AVI Publishing, pg. 306). He is talking about ambient temperature and I cannot vouch for his math. He is talking about the coffee industry in this book. In other writings he came out strongly in favor of freezing roasted beans as soon as the were roasted. By the way, I find that my home roasted beans taste best by three days degassing, and some varieties require only one or two days. Further deoxygenation by flushing the container with CO2 is recommended by many people for the assumed preservative properties. I am told that some canned commercially sold ground roasts are nitrogen flushed, then evacuated.
With regard to the issue I take with your second premise, surf Youtube and see, for a few junkyard dollars, how effective an old refrigerator condenser is at evacuating a gasket-sealed stainless steel storage jar with fittings drilled into the plexiglas lid, which can be bought at Target, if not found in a thrift shop.
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