Single dosing & storage in vials

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#1: Post by bean74 »

It's come up a few times in recent threads, likely a perennial topic, but my interest was sparked in a recent thread on single-dose grinders, by mention of storing open bags of coffee in test tubes or small vials. In theory, it's a minimal-volume sealed vessel, and can offer a potentially less-tedious workflow than weighing out 14g (or whatever) of beans for each shot pulled.

The primary complaint appears to be the tedium of loading those vials, upon opening a new bag of coffee. I thought I'd experiment some, here.

I measured the volume of my usual dose, which came up to somewhere near 45 mL, so I picked up a bag of 25 vials, 45 mL each. My thinking was that I could just pour the beans into a bowl, dip the vials into the bowl, and fill each to near the top, with just a final (and quick) weight check to add or remove a few beans to nail the final weight.

It turns out that just filling by eye, I'm within 0.1 gram on my first try. Not bad, although I quickly learned the idea of just dipping the vial into a bowl of beans will only work for maybe the first half of a bag, until the beans remaining in the bowl are insufficient for this technique to work. In any case, here's the first unit:

I'm thinking a boxed tray with 24 holes into which these vials are threaded from below, or dropped in from above, could make a nice loading mechanism. Insert vials, dump full 12 oz. bag of coffee into tray, shake until they all fall into the vials. 0.5 oz = 14g each. Heck, I could even design it to hold the tubes for storage. Sure, there will need to be some manual manipulation to get the weights right, but they'll all be starting from a point very close to target, unless I start buying beans with substantially different weight/volume.

Thoughts? It seems many of you have already been down this road.


#2: Post by Flannelsec »

I feel like there would still be enough manual intervention to not make this a time saver.

bean74 (original poster)

#3: Post by bean74 (original poster) »

I was worried about that, too. So I grabbed a funnel this morning and dosed out my open 12 oz bag. I didn't count, but I think it was close 20 vials remaining in the bag, and it went very quickly. I found that by eyeballing the fill to the bottom of the threads on the vial, I'm usually within 1% of my target. I would estimate about 10% fell outside that, at 2% target, which amounts to 4 beans on this roast. Spot-checking the weight and even knocking out a few beans from the vial was quick and easy.

So, initial test was a success. I'll stick with this method awhile, and see how it continues to work. For one, I need to figure out storage for all the rinsed and empty vials.


#4: Post by Flannelsec »

Interesting. Very nice. Unfortunately, I dose out two separate weights depending on if I need to do a double for myself and wife, or a single for just myself.I haven't been able to get vials that allow me to get that close.

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#5: Post by Christobol »

I think this exists for single dosing

bean74 (original poster)

#6: Post by bean74 (original poster) »

Some photos. Dumping a bunch of beans from the bag into the funnel, and then just shaking the funnel a bit, is the perfect loading mechanism. The hole on this funnel is the perfect size to let beans fall thru when I give it a jiggle, but not lose any when I lift it out of the vial. Dumb luck on my end, it just happened to be the only funnel in our kitchen.

These vials are liquid tight, so given the small air volume remaining once filled, I expect they should keep fresher than a rolled-down bag that's getting opened for single dosing 3x per day. Hopefully the beans have out-gassed enough in the bag before initial dosing into these vials, that I won't have any issue with pressure building in the vials, although I wouldn't really expect it to be a problem on this scale with this particular cap design, anyway.

The weight of the empty tube is tared out, so the number shown is just the bean weight (14.2g, for those preferring metric).


#7: Post by cmin »

I know the Weber Cellars have the release valve on the cap for off gassing/pressure, but does it make that big a difference? I don't think I've ever seen one post of someone doing their own cheaper bean cellars like this and having tubes explode


#8: Post by longpvo »

No, it's a marketing spiel. It's more or less a silicone slit valve injection moulded into the closure, by the time you receive you bags of of beans, the residual CO2 is insignificant to cause any harm to the beans or explosion to the container.


#9: Post by aspenextreme03 »

I have the craig lyn vials and use my v60 02 as a funnel and it fits perfectly. Also since they are flat it makes it much easier

bean74 (original poster)

#10: Post by bean74 (original poster) »

Just used my last vial of the prior bag, gonna dose out 24 more tonight. I bought a pair of plastic laboratory test tube racks, which fit nicely in the cupboard, and make storage and filling an organized and efficient operation. Overall, I'm happy with this solution, and I'm finding the beans smell much better after 8 days in the tubes than in any rolled-down bag... for whatever that's worth.