dosing with the hopper trap

[Kyle Glanville]

so...

i've recently noticed that if i open the trap door on the bottom of the hopper on the robur, then shut it, i have enough coffee between the bottom of the door and the burrs to grind a pretty consistent victrola dose. this seems like it would be great: i don't have to pay as much attention to when i shut off the grinder, the variable of bean weight in the hopper is eliminated, and the coffee is ground until almost all rampant grounds in the chamber are pushed into the doser.

i have a few concerns though:
am i allowing for too much popcorning in that little area?
the grind takes longer, so could i be putting excessive stress on the motor, especially after the grinding is done?
and one other i can't remember...

i dunno guys, whattaya think? is this a good way to dose coffee in a fast paced environment. do the cons outweigh the pros?

discuss

[Brent]

Hi Kyle,

Don't know the mechanics of it, but heres my thoughts on grinders in general.

I recall an alt.coffee post ages back where the comment was made that in effect the burrs had a shorter than spec life if you put a per shot dose in and only ground for the shot - effectively running with an empty hopper, or what you are describing (as my small brain understands it)

In which case, and it makes sense to me, as long as you are happy to replace the burrs more reguarly, and it simplifies things, then why not?

As for a busy environment - the fuel espresso bar at wellington airport in nz grinds per shot (super jollys I think) and they get queues 30 deep during the morning rush - and produce great shots.

So it comes down to what works I guess.

Personnally, I plan on changing the burrs (or organising it) at around the 50% of spec - so around 200 kgs on the mini, or 300 on the sj.

But I have been accused of being obsessive before!

Brent

[nick]

Kyle,

That's exactly how Hornall rocked it at the USBC this past year.

I was worried about popcorning... but in theory, there are always 'fines,' and how they effect your extraction... well, that's a whole 'nuther discussion, I guess. If the hopper-door method indeed produces a consistent shot, then as long is it's "good..." ya know?

[barry]

I recall an alt.coffee post ages back where the comment was made that in effect the burrs had a shorter than spec life if you put a per shot dose in and only ground for the shot - effectively running with an empty hopper, or what you are describing (as my small brain understands it)

iirc, that was in reference to the solis grinders, and others which use the same burr set. those burrs are forced apart to the "proper" gap by the resistance of the coffee beans/grounds; they have a floating upper burr carrier. on a very fine grind, as for espresso, running the grinder empty can result in burr/burr contact.

--barry "a.c since 2400 baud"

[barry]

That's exactly how Hornall rocked it at the USBC this past year.

and i'm pretty sure he lost points because of it.

[Kyle Glanville]

so, barry.. you think its a bad idea? too many fines? too hard on the grinder?

[barry]

there are ongoing discussions about the effects of "popcorning" in grinders, and the effect it has on the grounds and subsequent shots. those discussions won't end until we get some serious grind analysis done. because there is the potential for popcorning to be a negative factor, and it's not very likely that it will be a positive factor, the prevailing attitude seems to be it should be avoided, especially in competition.

that said, i don't worry about it in day to day affairs. i chuck a scoop of beans in my cupping grinder and let 'em dance. the versalab grinder also seems to have no problems with it, but that might be a result of the dual burrset (i've got one on loan for awhile).

i can't see that it's hard on the grinder, except, perhaps, that the increased motor run time might cause cooling issues on mazzers. that's a tough one to judge w/o measurements, since the motor is really spinning under a very light load compared to a full-on loaded grinder.

[Alistair Durie]

as this could be related to all grinders i have moved and renamed it 'dosing with the hopper trap'.

[phaelon56]

I assume you're dosing at about 21 grams and using a "triple" basket? Even if popcorning is occurring I see one big advantage. When things get slow and you may have ten or fifteen minutes whefre the grinder is not active... using the traditional method means that you have some chunks of partially ground beans still sitting in the burr area. These go right into the next shot you make. Dosing with the hoper trap means you have 100% freshly ground beans every time even at a slow time of day.