Hi everyone,

Please bear with me, and apologies if this has been answered umpteen times before.

Until recently, I've exclusively single-dosed my Vario. This is mainly because - with my work schedule, commute, and kids - I don't have time to pull shots every day. So my routine and usage pattern is conducive to single dosing, without keeping beans in the hopper.

Yesterday, I decided to experiment with a full hopper and dosing by timer. I settled on 9.4 seconds for 18g. I weighed each dose afterwards on my 0.1 scale and there was some variation between doses (0.5grams or so)

My questions are, in your experience:

1) What factors affect the grinder's output per second?

2) Do different beans grind at different rates, hence, affecting your set time for a particular dose?

3) Do different grind settings, coarse vs. fine, grind at different rates? (I suspect so)

4) Does a full or near empty hopper affect the grind rate?

5) How much variation, from dose to dose, do you experience when grinding by timer?

6) Overall, how accurate is the Vario for timer based dosing?

7) I know the Vario has low retention - so do you purge any grinds if it has been sitting for a while?

Thanks for your help in advance!

Hi Ryan,

I don't know the Vario that well, so hopefully some people who do will follow along and fill in the Vario specifics, but maybe I can help with some of the generics.

1) What factors affect the grinder's output per second?

The bean, the roast, oiliness, bean moisture, bean density, post-roast age, humidity, condition of the burrs, whether the grinder's just been cleaned, burr alignment... the list goes on.

2) Do different beans grind at different rates, hence, affecting your set time for a particular dose?

Yes. But usually not by much. Once time dosing is dialed in for a given coffee, switching to annother usually doesn't require much in the way of adjustments.

3) Do different grind settings, coarse vs. fine, grind at different rates? (I suspect so)

Yep.

4) Does a full or near empty hopper affect the grind rate?

Yes, at least for grinders like the Vario which don't have augur feeds. As the hopper gets low, the dialed-in time will usually yield a lower dose. But as it gets close to empty, the dose actually goes up.

Why? Don't know.

5) How much variation, from dose to dose, do you experience when grinding by timer?

That's very much grinder specific. But...

To generalize: As a practical matter, if you cut at the blond point, and your dose (whatever it is) is within the good range for the basket, it's not a problem.

To quantify: If the pull is cut by blond point, a dosing error bar of plus or minus 5% from ideal is pretty much undetectable in the cup.

To repeat: It's more about what works for a given basket than anything else.

6) Overall, how accurate is the Vario for timer based dosing?

Good enough.

7) I know the Vario has low retention - so do you purge any grinds if it has been sitting for a while?

It's never a bad idea to bump and brush. Because Varios do have very low retention, yours should never need anything close to a full-dose purge.

Hope this helps,
Rich

boar_d_laze wrote:

Hope this helps,
Rich

Thanks BDL! Appreciate your help. I've noticed you're very generous with your time and sharing your expertise, on both CG and HB. Cheers.

bdl is spot on! this is my take...

canuckcoffeeguy wrote: 2) Do different beans grind at different rates, hence, affecting your set time for a particular dose?
3) Do different grind settings, coarse vs. fine, grind at different rates? (I suspect so)

yes, these vary enough to make a significant difference (maybe up to roughly 10%, perhaps--i.e. 1.5 sec worth of grinding in a 15 sec grind for a 18-20 g shot), which is why i weigh first and then single dose. light roasts take significantly longer to grind than dark roasts on my b-vario.

canuckcoffeeguy wrote: 4) Does a full or near empty hopper affect the grind rate?

not a whole lot--not nearly as much as 2 and 3 above. when i went from regular dosing with variable levels of beans to single dosing, it didn't seem to make a huge difference in total grind time...

canuckcoffeeguy wrote: 5) How much variation, from dose to dose, do you experience when grinding by timer?
6) Overall, how accurate is the Vario for timer based dosing?

not that much variation--it's pretty accurate if you keep other variables (bean/roast, age) consistent, but you should definitely consider single dosing by predetermined mass if you're only pulling a few shots each session! (if you're pulling more than that, dialing in the grind fineness and grind time is probably worth your while at the beginning of each session, i would imagine)

canuckcoffeeguy wrote: 7) I know the Vario has low retention - so do you purge any grinds if it has been sitting for a while?

yes, but by running perhaps 1g worth of new beans through, max...depends who you ask, but i'm pretty sure the retention is quite a bit less than 1g. you can verify this by running some darkly-roasted beans through, then some lightly-roasted beans--how many beans does it take before the grinds are pretty much all light-colored?

1. See #3
2 Yes, minor adjustment though
3. Yes
4. I keep 1/4 full, although its pretty consistent and popcorning is minimal when lower
5. Not Much
6. Fairly accurate; works
7. #3 button is set for 2.5 seconds. Mostly used at bean changes, after brushing chute with a dedicated shaving brush