# Compak K-10 Fresh Single dosing and retention issues / rubber lens hood mod.



## billcoxfam (Jan 8, 2013)

I've had my nearly new K-10 F for 2 months and it's great. No messing about with brushes, scales, dosers anymore. Once it's dialed in I get a timed, measured dose in the centre of the portafilter needing only a gentle tap and light tamp.

Ok, if using the hopper, there will some part ground beans retained in the grinding chamber which would be a concern to some. This has led to some home users of Compak's conical burr grinders to opt for the dosered version in an attempt to reduce retention and to permit single dosing.

With some trepidation I started unscrewing the K-10 today for cleaning and also to remove a small plastic flap, which doesn't seem to serve any purpose, from the exit shute.

Having removed the upper burr and thoroughly cleaned the grinding chamber I successfully reassembled the K-10 F.

As a test I dosed 16g of beans into the neck of the grinder with the hopper removed. This produced 12.7g of ground beans, 3.3g retained somewhere in the grinder. I then fitted the rubber lens hood hopper from my retired Mazzer SJ and a gentle press with the palm of my hand expelled a further 2.4g leaving just 0.9g retained.

I assume that this 0.9g will be the first out from the next grind. As the test was done with a fairly lightly roasted bean I hope the next single dosing tomorrow with a darker bean will clarify the matter.

My conclusion, for what it's worth, is that the K-10 F with the rubber lens hood added is every bit as capable of single dosing as the dosered version if required and has all the benefits of "on demand" grinding. No more sweeping, brushing and thwacking!


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## 4085 (Nov 23, 2012)

Bill, the retention is stored between the burrs and the exit chute normally. You would need to take the whole top off to view it. I suspect if you did, you would find an awful lot more than you think. You cannot effectively single dose with an on demand conical. No weight of beans means no pressure to push them through. You can effectively single dose a dosered version and with the two mods my k10 pro barista has I can dose 18 gms and get around 17.8 out


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## billcoxfam (Jan 8, 2013)

I have had the top off and the upper burr removed so I started with a clean machine, no grinds retained. There is now 0.9g in there somewhere.

The question I want to answer is whether this 0.9g is somehow locked in or, if I continue to single dose for a while, whether this 0.9g will be the first out from the next grind with the last 0.9g of the next grind left in the machine.

The puff of air from the rubber lens hood did a great job of clearing retained grinds from the machine as it did on my previous grinder.

When you say you can dose 18g and get 17.8g out, is that from a clean start i.e. having exposed the grinding chamber and thoroughly cleaned (as I did) or is some of the 17.8g out the "old" beans from the previous grind. I haven't seen the K10 pb close up so I don't know if most of the grind can be expelled each time. I can't see why there should be less retained in the grinding chamber on the dosered version than on the F.

Anyhow, I had been rather concerned about comments on various forums about large amounts of grounds retained in the K-10 F and I was quite pleased to prove to myself that if I choose to single dose, the rubber lens hood mod makes this a viable option.

The question of the quality of grind when there is no weight from a column of beans is one for another day! That must be an issue for single dosing for both dosered and on demand grinders. I suspect that my palette isn't up to noticing a difference though.


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## 4085 (Nov 23, 2012)

I suspect there is more to this. Conical burrs being very deep retain the coffee within the burr set that I doubt the lens mod will touch. Perhaps others with more idea than I will chip in. The figures I stated were not from a clean start but unless you have one of those grinders that everyone knows has zero retention, believe me you will have it somewhere


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## coffeechap (Apr 5, 2012)

If you let the k10f run out completely by single dosing the figures should be as quoted, you then should be able to blow through the grind path and clear out more of the grinds, I have found that the grind consistency is compromised slightly and it takes some 45 seconds to completely finish grinding a 18 gram dose on the k10f


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## Coeos (Sep 30, 2018)

Hi,

I know your post is pretty old now, but as I just bought a used K10 fresh I'd like to know if you found a good method for single dosing on this machine over the years?


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## billcoxfam (Jan 8, 2013)

I'm still single dosing on the K10F using the rubber lens hood as a blower. I sometimes add a couple of drops of water to the beans to reduce static. A clear plastic lid from a pot of Tesco cream forms a good, fairly airtight lid to the hopper and a few presses as it's grinding clears most of the grounds. 16g takes about 10 seconds. It works well enough for me.


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## level3ninja (Sep 7, 2017)

Can you please share the dimensions / details of the lens hood you're using? I've never bought one before so don't know what to look for. Cheers


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## billcoxfam (Jan 8, 2013)

I'm still using the same rubber lens hood for daily single dosing with my K10F seven years on. The method works for me although the experts with more discerning palates would probably still disagree!

The hoods are listed on eBay 58mm 3-Stage Collapsible Rubber Hood For Lens With 58mm Screw Thread UK STOCK
If I remember the metal screw thread pulls off easily and the rubber hood then fits easily into the grinder.

Hope it works for you.


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