Why is it so ?

derrilex · November 2014

OK, I find this interesting and mysterious. With the first coffee of the day or any coffee with a 3/4 hour break since the last one, I get a huge difference in the colour of the shots. I grind for about 5 seconds and discard ( about half a dose worth) and I know the Eureka retains very little ground coffee. The picture shows 2 brews, same grind, dose, tamp etc... The darker one was first. Both tasted fine by the way. But why the difference ? There are no stale grinds. I thought it might be bean exposure in the hopper for the second shot but those beans are not really exposed like the top layer. More exposed than what's in the throat of the grinder though. Thoughts.

cosmic_couple22 · November 2014

Do you do the grind and discard before the first one D.

RichardM · November 2014

I get the same thing. I put it down to a temperature variance, and seeing as we both ahve the same machine, it might just be a characteristic of the Mitica style range?

derrilex · November 2014

on 1415966418:

Do you do the grind and discard before the first one D.

Did you read the post CC ? :D

derrilex · November 2014

on 1415966714:

I get the same thing. I put it down to a temperature variance, and seeing as we both ahve the same machine, it might just be a characteristic of the Mitica style range?

Very interesting RM. If I only make one I obviously have no idea. But every single time I make 2 I get this colour difference. I've never really taken much notice of the results if I make 3 or 4. Must do that one day

Koffee_Kosmo · November 2014

I have had a long think about youre query And this is what I have come up with - It could possibly be aeration differences of the brew water and how it travels through the pump and feeder pipe work to the brew head It may also be aeration differences created by the brew head screen itself Like to see other views as they come KK

derrilex · November 2014

True however, if there was a variation I would think it would be random. As it is, every first shot is darker. Also, I forgot to mention the mitica gets a 5 second flush before every shot. If it's percolating I flush until no longer audible.

cosmic_couple22 · November 2014

Was just clarifying that before the first coffee of the day you did the discard not just every subsequent coffee.

Koffee_Kosmo · November 2014

on 1415969689:

True however, if there was a variation I would think it would be random. As it is, every first shot is darker. Also, I forgot to mention the mitica gets a 5 second flush before every shot. If it's percolating I flush until no longer audible.

I suppose you can borrow my laser cut competition water screen to test my theory ? Or see if that makes a difference KK

Brett H · November 2014

I used tho get this issue with my HX. Not as stark a colour difference but the first shot would pour great and the second slightly loose. I haven't noticed it with the double boiler. What I Have noticed with the DB is that the first shot of the day flows more freely than the second which sometimes chokes. I've aleviated this by flushing prior to the first shot. I don't do a flush at any other time with the DB! I put it down to every machine having its own foibles!

Koffee_Kosmo · November 2014

It can also be accumulated dried coffee oils under the screen / brew head area overnight Understanding that you have water flushed prior to making a coffee, however the coffee oils may only dislodge under pressure and mingle with the first shot Time for second shot and it's no longer an issue The only way to check this theory is to remove the screen and clean it along with the exposed brew head before you make coffee KK

Brett H · November 2014

on 1416003015:

It can also be accumulated dried coffee oils under the screen / brew head area overnight Understanding that you have water flushed prior to making a coffee, however the coffee oils may only dislodge under pressure and mingle with the first shot Time for second shot and it's no longer an issue The only way to check this theory is to remove the screen and clean it along with the exposed brew head before you make coffee KK

Yep, in a dirty machine that's a great theory. Mine was super-clean this morning, no issue but none expected either due to the flush. I wonder....

derrilex · November 2014

All food for thought fellas. Ok more info. At days end the head gets flushed, cleaned and backflushed with the blind - no chemical. Full chemical backflush, screen removed and cleaned etc... Monthly.

steve82 · November 2014

I will guess its to do with temps, a combination of HX and slightly hotter group. For that first shot or after its been sitting, you could try a 10 second flush when you first walk up to the machine, then commence shot prep ect and continue on with your normal routine.

mycuppa · November 2014

Guys, guys, GUYS...........please........enough with the over-complicated theories. It's really simple - you need to grind more than 5 secs for the purge to be effective and flush your machine a touch longer. Not referring to you D., but in general what people think a grinder retains and what it actually retains are different. The purge is not always 100% effective (stuff gets clogged on the sides and all sorts of places) and the duration of a purge varies depending upon many factors such as grinder design, how clean it is (the grinder), the types of beans/ground and relative temp+humidity - yes, it's scientific........or you can just do it simply by testing each morning how long you need to run it so that shots are the same (or similar). As a person who has to do your same routine more than a dozen times a day, 6 or 7 days a week, depending upon what grinder I am doing a purge on, I can run up to 50g through it before I am happy. I will let you in on a big secret.........it's impossible to get them to be precisely identical without wasting a lot of coffee.

conikal · November 2014

on 1416009025:

Guys, guys, GUYS...........please........enough with the over-complicated theories. It's really simple - you need to grind more than 5 secs for the purge to be effective and flush your machine a touch longer..

Jeez !... I don't doubt that a 5 +sec purge would clean out any stale grinds! but , it would also flush out my wallet equally quickly ! 5 sec on most Conicals or pro grinders would be 20+ gms! and few grinders have that much retention when single dosing. ( if you are hopper feeding for just a shot or two,...well you are already wasting good beans !)

Kevohere · November 2014

on 1416009025:

Guys, guys, GUYS...........please........enough with the over-complicated theories.

I don't think they are over-complicated at all! What's wrong with endeavouring to diagnose a difference in the cup? Most of us coffee connoisseurs (oops, nearly said sno ..nobs :stir) here, like to question and share theories on our experiences. One question I'd like to ask D, as I haven't seen it mentioned as yet; Are these different colour experiences only occurring with blends or also with SO? Cos my mind (or ignorance if you like) questions how a blend of 3 or more beans could pass through the grinder at the exact same ratio. As D states; "Both tasted fine". Personally, I'd be happy with that. But, in an effort to keep the (non) complicated discussion rolling, I then would ask: 'Given the time between the cups factor, were there any noticeable taste differences?' Over.... :coffee2:

mycuppa · November 2014

Looking at the colors presented in the pics, allowing for light distortion from photographic shading and based upon my own experiences.......there would be a difference in the cup - perhaps less so with milk and would in fact be quite distinguishable to those with a developed palate (not suggesting that yours is not D.!). I wasn't there, can't taste......so don't know.............I'll leave it to the Miss Marple's to solve the mystery then.......obviously I have no idea what I'm talking about.

mycuppa · November 2014

on 1416013897:

Jeez !... I don't doubt that a 5 +sec purge would clean out any stale grinds! but , it would also flush out my wallet equally quickly ! 5 sec on most Conicals or pro grinders would be 20+ gms! and few grinders have that much retention when single dosing. ( if you are hopper feeding for just a shot or two,...well you are already wasting good beans !)

I don't know what type of Grinder Alex uses (nor does it really matter)......but the advice was offered that he needs to purge more and the caveat at the end of my explanation referenced that it does consume a lot of coffee. It is a simple solution to a common and universal problem that effects almost every espresso system and just happens to also consume dis-proportionate amounts of emotional hysteria on coffee forums - a.k.a. grounds retention. If you worked in a specialty cafe using a Conical or "pro grinder" (whatever that means) and did not purge out at least 5 seconds first thing in the morning, then I would pity the poor customer receiving that first cup. Some cafes will consume many hundreds of grams of coffee first thing in the morning getting the stuff "dialed in" which by it's nature purges out the majority of clingy retained grounds and brings all things back to a consistent point. We have cafes who use plumber's rubber plunger (not the coffee makers) to "pump out retained grinds via high-blast pressure), small compressed air blowers, vacuum cleaners or they remove the top burr assembly completely to clean and re-dial the grinder (sometimes wasting up to half a kilo). Running freshly ground coffee through is but just one method of displacing retained grinds......albeit not the most effective.

derrilex · November 2014

High guys. Righto. The grinder is a near new Eureka zenith club. 60 mm flat. Scored off ebay brand spankers for $200. Jeff, I only say retains bugger all as I had the top burr off it the other day after it ate a rock and there was bugger all, well bugger all compared to my other Eureka. And yep, " both tasted fine" was after milk. My pallette is as sensitve as the sole of my foot in case you're wondering. Green apples are a pipe dream for me :D as far as wasting coffee goes, I don't care. I'd rather dump a shots worth of beans than buy a shit coffee from a cafe. The cost to me is near zero anyway. However, tonight I ground and dumped 10 secs worth. The result was much better and the taste was epic ( to me). The colour difference intrigued me rather than upset me. As long as the cup is not a sinker it's all good. I think my future grind and dump ratio will depend on my stock of rested brown :D

derrilex · November 2014

First shot on the top. Panama la esmerelda (pshite)

Koffee_Kosmo · November 2014

Well it's what's in the cup that counts :thumb: As long as you enjoy it then all is good KK

conikal · November 2014

on 1416047830:

, tonight I ground and dumped 10 secs worth. The result was much better and the taste was epic ( to me). The colour difference intrigued me rather than upset me. :D

So, just to be clear, are you saying, that the longer purge grind reduced the dark colour of the first shot. . ...but there was still some "lightening" of the crema on the second. .? ...can you clarify, ...is your starting point ( before the initial purge) a hopper and grind chamber full of beans/ grinds as left from the previous session, or are you starting with an empty hopper and grind chamber ?

Kevohere · November 2014

on 1416033213:

.......obviously I have no idea what I'm talking about.

Who said that? I can't recall any of your posts that haven't enlightened/taught me something in some way. :thumb:

derrilex · November 2014

on 1416094505:

So, just to be clear, are you saying, that the longer purge grind reduced the dark colour of the first shot. . ...but there was still some "lightening" of the crema on the second. .? ...can you clarify, ...is your starting point ( before the initial purge) a hopper and grind chamber full of beans/ grinds as left from the previous session, or are you starting with an empty hopper and grind chamber ?

Ok, my hopper is never full. It normally has upto 200 g in it. However, the grind chamber and doser are empty.well, as empty as the grind chamber can be. So to clarify, with the longer grind and dump the first shot is a touch lighter, the second shot is much closer in colour to the first but is still lighter. As far as flushing the hx goes, I always give it around 5 secs which is long enough to hear it flashing in the system ( thus requiring more flushing). The second shot gets a five second flush too but more to get any grinds off the screen from the first shot. Over temp is never an issue on the second shot.

conikal · November 2014

on 1416114310:

Ok, my hopper is never full. It normally has upto 200 g in it. However, the grind chamber and doser are empty.well, as empty as the grind chamber can be.

I'm struggling to understand how you can have an empty grind chamber if you normally keep beans in the hopper ?

Koffee_Kosmo · November 2014

on 1416116007:

I'm struggling to understand how you can have an empty grind chamber if you normally keep beans in the hopper ?

Some hoppers have a gate ? KK

derrilex · November 2014

on 1416116007:

I'm struggling to understand how you can have an empty grind chamber if you normally keep beans in the hopper ?

Well this is just getting stupid now. Yes, ok there are beans sitting on top of the burrs in the grind chamber. Are they ground, in part probably yes. Makes no difference anyway as whatever residual crap is left after the last grind is flushed out and dumped with the next. And yes, there is a gate on the bottom of the hopper but I don't use it often.

conikal · November 2014

on 1416135253:

Well this is just getting stupid now. Yes, ok there are beans sitting on top of the burrs in the grind chamber. Are they ground, in part probably yes. Makes no difference anyway as whatever residual crap is left after the last grind is flushed out and dumped with the next. And yes, there is a gate on the bottom of the hopper but I don't use it often.

Stupid, why ?....it makes your comment about " bugger all" retention totally irrelevant , and explains why a 10 sec purge made a big difference ! Do you not realise how much grinds and part beans are in the grind path, or the significance of leaving the grind path full for 3/4 hour between shots, and that your original few seconds of purge is unlikely to have been emptying out ALL those stale grinds ?.......and then wondering why the first shot is different in colour ?

samuellaw178 · November 2014

The discussion seems to surround the stale grind. If anything, stale grind tends to run faster and thus lighter-color shot. What's happening here are the opposite. My take is on the hx temp as hinted before. 5 sec flush is good for bringing down the temp after a long 30-45 min warm up. But another 5 sec flush after the first shot will definitely bring it down lower than the point before. Mitica is semi-commercial so the recovery time probably isn't as steep as what we thought.

derrilex · November 2014

on 1416172763:

Stupid, why ?....it makes your comment about " bugger all" retention totally irrelevant , and explains why a 10 sec purge made a big difference ! Do you not realise how much grinds and part beans are in the grind path, or the significance of leaving the grind path full for 3/4 hour between shots, and that your original few seconds of purge is unlikely to have been emptying out ALL those stale grinds ?.......and then wondering why the first shot is different in colour ?

It's stupid because it's nitpicking. Retained grinds, to me, means actual ground coffee that has left the burrs but not the chute. That is called grind retention. Every grinder ever made will have partially ground beans sitting on or in the burrs and they don't count as far as I'm concerned. Of course I realise the significance of leaving the grind path full for 3/4 hours between shots. It's not like I or anyone else does it deliberately. It is what it is. I always new what the issue was and the way to solve it. I just put it out there to see how others responded. I shouldn't have bothered.

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