# Grinder purging between grind adjustments



## fatboyslim (Sep 29, 2011)

As title suggests I'm just wanting to gauge what people feel is an acceptable amount of beans to purge through your grinder for the first shot and also between grind adjustments.

I know in a cafe environment you may use a whole dose (14-16g) to purge the grinder when adjusting grind size or between gaps in service but that is just not viable in the home environment.

At the moment I can justify using about 3-4g for my super jolly before grinding for my first shot and again between adjustments. I know it may not be doing a total purge but I have got into the habit of collecting all my purged grounds in a little tub and at the end of a weekend it can be 30-40g! Makes me sad to waste coffee like that.

Just interested to know other people's view on this.

(Gary surely Roy needs a pretty hefty purge with his humongous burrs?).


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## MikeHag (Mar 13, 2011)

At home I try to minimise the dreaded waste by stopping grinding early (say at around 13g) then using both ends of a small brush to empty the chute and then continue filling the basket. That way no purge is needed on the next shot.


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## lookseehear (Jul 16, 2010)

I think it depends on the grinder. For my SJ I'm fairly sure I get almost all of the beans out by sweeping etc so I don't worry too much. If I wasnt single dosing and I wanted to be pretty confident between changing settings I think I would purge 4g ish as the chute holds about 2g then another couple of grams part way through the burrs.

Sent from my Nexus 7 using Tapatalk 2


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## garydyke1 (Mar 9, 2011)

I single dose Mark. 18g in 17.999g out, good ole pastry brush . Roy retains 2g in chute , so I could throw 20g in and clean up after if I'm in a rush


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## jimbow (Oct 13, 2011)

I must admit my grinder has quite a large retention so I purge quite a lot when changing grind to avoid false positives whilst dialing in. I experimented with alternating beans and Grindz to work out the amount I need to purge.


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## garydyke1 (Mar 9, 2011)

Had a play this morning, grinding 3 shots. Mazzer royal grind retention 1. 2.1g 2. 2.2g 3. 2.2g. This is pretty consistant & actually similar level of retention to my old Mini-e. Not bad for a 83mm beast. The chute path isnt any deeper/longer than an SJ I dont think. Your purge of 3g would be about right if keeping the hopper full.

Shop owners would benefit from knowing exactly how much to purge for each grinder, I suspect at those volumes the waste costs could mount up!


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## funinacup (Aug 30, 2010)

A grinder that has programmable timed doses would come in very handy here to save any guess work / waste when changing grind settings.

I think the Anfim chute holds around 8g though. Surprised that the SJ/Major chutes hold less!

Michael

Fun in a Cup Coffee Training


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## fatboyslim (Sep 29, 2011)

Just to be clear I'm talking about the amount of beans needed to remove all grinds still in the burrs from the previous grind size.

If you try dialing in a new bean you may need several adjustments and that can mean several purges to make sure all the old grind leaves the burrs. That can end up being quite a lot of beans even before you've tasted a shot. I think 3-4g works for my 64mm burrs but I could be wrong.

Not worried about retention as its pretty low on the SJ until you come to clean out burr carrier etc. I use a small flexible stick to empty the chute.


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## garydyke1 (Mar 9, 2011)

So youre effectively 'cleaning' your burrset with fresh beans every time you change the grind setting ?? If there is nothing in the chute and you've 'pulsed' the motor so nothing else comes out, then whats left??

edit - Video of what you mean goddamit! : )


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## MikeHag (Mar 13, 2011)

Think I know what you mean. Grind adjustments should never be made when the motor is off, so there's always waste. Pain in the arse, especially with fast grinders and especially if its a grinder that takes a little more work to dial in. There is no acceptable amount, I think. It takes what it takes. One of the things I like about the K10 is how easy it dials in, so waste is reduced. One of the things I don't like is how the fast grind means there's perhaps 10-15g (guess) of waste for every adustment (again, I clean out the chute first), and if you don't get it right first time then that's another 10-15g wasted. I'm buying 1kg bags now!


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## garydyke1 (Mar 9, 2011)

I only have the motor running when adjusting finer, then again I never do this with any beans in the throat either - its too wasteful


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## rmat (Aug 25, 2012)

I only grind for a double + 1g in my sj. If I am in the ballpark I adjust dose. A curved toothbrush for sweeping out the chute while grinding to avoid heating the grinds. When washing up I'll hoover out the sj each time and once a week scrape the grinder paddles. On a particularly bad roast the burrs get cleaned. HTH


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## fatboyslim (Sep 29, 2011)

It may be that when you pulse the motor that all the grounds are cleared from the burrs but on my SJ if I pulse the motor then disassemble burr assembly its immediately clear that there are still lots of grounds stuck inbetween the burr 'teeth'.

Whilst some of these may not actually be replaced by purging beans through, I believe a small purge does have a beneficial affect on shots (as far as getting better timing separation between grind adjustments).

Would be happy to be proved wrong. All of this obviously only really applies to single dosing since that is what most of us do anyway. As Mike said, when you have a bean hopper attached, its necessary to run the grinder to make adjustments and so you are inadvertently purging whilst making the adjustment.

I'd love to be told that I didn't need to purge but say you pull a shot and need to go finer on the grind. If you dose straight away without a purge what percentage of that dose will be the old grind size, maybe 5-6% which may impact on flow rate and/or flavour?


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