Rossi RR45 single dose mod?

Grinders are one of the keys to exceptional espresso. Discuss them here.
David6FL

#1: Post by David6FL »

Is there some way to modify a Rossi rr45 grinder from a hopper type to a single dose? If so, where might find the needed parts? I ran into a listing on eBay for a single doser so Rossi must have made them at some point. I have just about given up on mine with the hopper. The weight dropped is inconsistent, and it takes a substantial amount of beans to find the right grind every time I get a new lot of beans. I end up with too coarse or too fine coffee because it takes a lot of beans to get enough coffee in the hopper for the doser to work. Also, the weight dropped seems to vary depending upon how much ground coffee is in the hopper. With the economy the way it is, I am not ready to spend a lot of money on a single dose.

I am trying to get 18 grams of coffee that will give me a 27-second pull.

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Jeff
Team HB

#2: Post by Jeff »

Search turned up Doserless mods for a Rossi RR45

In general, you can't make virtually any hopper-intended grinder, of any make, into a good single-dose grinder because of the design of the burr chamber and exit chute. There will be significant retention with most of the classic designs on the market. As you have found out, that exchange can significantly impact later shots if it is not nearly completely purged out. If you don't grind a lot of shots in a session and especially if you're grinding medium or darker beans, you might be better off with one of the better, modestly priced hand grinders rather than trying to make the Rossi into something that it may never be.

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JohnB.
Supporter ♡

#3: Post by JohnB. »

Jeff wrote:In general, you can't make virtually any hopper-intended grinder, of any make, into a good single-dose grinder because of the design of the burr chamber and exit chute. There will be significant retention with most of the classic designs on the market.
With a little time, ingenuity & few dollars you can modify some of the older commercial grinders into decent single dosers. I single dose with a K30, Super Caimano & a K10 with minimal retention. The flat burr grinders require use of a bellows to purge the grinds & both have custom throat tubes.
LMWDP 267

marcism

#4: Post by marcism »

So I attempted to do exactly this a few years ago with... let's say less than stellar results. The reality is that so much coffee gets caught in the chute on the RR45 that there's only using a bellows to get it out as a solution, and the you need a proper funnel attachment to the exit chute, and a way to seal the bellows in, and a it needs to give you a decent way to dump in beans that stops them popping up, and then you....

End up just buying a relatively cheap hand grinder that, these days, does absolutely incredibly espresso and single doses with infinitely less work.

TLDR: don't bother with the RR45.

jpatrickramos

#5: Post by jpatrickramos »

Or, there's a rather simple solution to all the nonsense..



I only "lose" about .1 to .2 grams per dose, and those are what stick to the wagon wheel inside the doser body.

austted

#6: Post by austted »

I did a single dose mod on a Rossi RR45 some time ago using an 'octopus balls' funnel.

Details here https://coffeesnobs.com.au/forum/equipm ... 45-grinder

Also did a similar on on a Compak K8.

I have since bought a Niche Zero but my son is the happy owner of the Rossi.

Ted