I am interested in the Eureka Olympus for single dosing. I was wondering if I could get users of this grinder experiences with grind retention. I saw a video from a retailer that showed 3.5 grams for grind retention. Has this been your experience? If not, what was the grind retention that you found? This is without the Eureka blow system being used.

Also, how well does the Eureka blow system get rid of the grind retention?

From my experience with stock burrs (steel) the stock retention is about 3 grams as you mentioned. Problem is it tends to be quite random, so it's a bit frustrating in single dose mode. Generally you will add a few grams more than you need and either you get the right dose or just remove the extra.


Also bought the blow up hopper. The design is a bit flawed from the factory:

[*] Blow up hopper still has vanes for the chute
[*] It does not fit flush in the grinder: it has some creases which actually grip the funnel.
[*] The lid doesn't have some sort of valve, so on the upstroke it will pull up air and grinds + chaff from the grinding chamber. All this will then come out of the vanes and not tight fit and on the outside of the grinder + motor vents It's not actually visible but over the span of 1 month for example you get quite a big deposit of coffee on top of the grinder ( also under the little plastic cover on top and probably on the motor inside)

Luckily you can solve this problem by taping the neck and the opening for the hopper chute, thus creating a tight seal.

I am now getting between 0 and 0.2g retention with light and medium coffees. Also the grinding is quite fast (4s ) and very little popcorning.
What I do is I also keep constant pumping during grinding and use a portafilter funnel.

Another thing to keep in mind is that darker roasted coffees might not work so well in this setup. Lots of static means the pump won't be able to clear the chute.

Mesmer wrote:
Luckily you can solve this problem by taping the neck and the opening for the hopper chute, thus creating a tight seal.
.

I'm curious, are you able to show some pictures of this set up?

Sure, here it is:

By the way, forgot to mention a big improvement since using blow up hopper: absolutely no clumping, even on very fine gind settings.


The taping: i will replace with black tape soon. Only had blue in the house, it is electrical tape.



Here is the business end of things. As you can see, it manages to clear the coffee "plug" which normally sits behind that clump crusher.



If only Eureka figured out a way to shorten the long chute, maybe like in a Monolith.

I measured it the right way some time ago and that was 8gr. That's with 10gr in the hopper and taking all of the whole beans and fragments out so that you also have the retention which is in the burr chamber when you're using a hopper. Grinding empty first will give a false result as you also grind out the grounds in that spot which will be there with normal use. The chute retained just over 4-5gr when you really do your best to get everything out.

Wow, 8 grams would be a lot for me. I am probably not going to use the blower since I don't want to use tape.

In the Clive Coffee video here, they only measured 3.5 grams for the Olympus http://www.youtube.com/watch?v=3_eWwZbEhrI?t=326. I am having a hard time visualizing/understanding the different ways of measuring. How was the way you tested different to the way they tested? Or better asked, why are their numbers different?

NOTE: If you fast forward to time mark 5:20 that is where they are testing the Olympus

Mesmer wrote: Also the grinding is quite fast (4s ) and very little popcorning.

Is this with single dosing? Others with this grinder have reported around 16 seconds with single dosing.

I upgraded my standard hopper to the Blow Up version and found exactly the same problem as mentioned earlier in the thread - coffee grounds getting blown out of the top of the grinder due to the fitting between the hopper and grinder not being snug enough.
I also resorted to tape but decided to apply the tape to the top of the burr carrier where the hopper mates up to it, which creates a tight fit. This prevents coffee spewing out. It also has the added advantage that it can't be seen unless you lift up the black plastic collar that sits on top of the upper burr carrier.
The retention is normally 0.1g, occasionally 0.2g. With this mod, I'm happy with it as it saves me purging out the best part of 5 grams every time.
Grinding time is around 6 seconds for a very fine grind (60+ second shots) and around 4 seconds for a 'normal' espresso grind. Both single dosing.

Why not get a Compak E5? great for single-dosing and no special considerations.