# Inconsistent Shots on Classic



## Finley (Oct 19, 2014)

Hoping some of you may be able to help me figure out what I'm doing wrong as I've been struggling recently pulling consistent shots. Just now I pulled shot 1 @ 32 seconds then a few minutes later shot 2 @ 19 seconds! :/

I have attached a thermometer to the boiler wall which read 110 degrees for both shots (I used the steam button to cycle the temperature a few times so it didn't drop or go higher). Figure group head should be roughly at the right temp this way?

30-40 mins warm up time, opv mod, everything is weighed - 17g coffee in 34g out (latest hasbean IMM). Grinder is an MC2 and I'm using a bottomless portafilter. I also turn the steam button on for a few seconds just before the shot to try and keep the temps a bit more stable.

Any tips would be very welcome, still very new to this so probably something obvious but I'm struggling to understand what is causing this. Let me know if you need more information as I'm sure I've missed things out!


----------



## Kman10 (Sep 3, 2014)

Are you steaming after first shot?


----------



## Finley (Oct 19, 2014)

Not this time just 2 espressos


----------



## Kman10 (Sep 3, 2014)

Maybe try running some water through group after first shot an then do second, I'm still very new myself


----------



## froggystyle (Oct 30, 2013)

You sure your distribution and tamp pressure are consistent?


----------



## Finley (Oct 19, 2014)

I was thinking that, I currently grind straight into the PF and tamp after a light tap (started doing that after watching the new 'learn coffee' youtube videos). I measured 30lb a few times but don't tamp as hard now, perhaps I should start measuring that again? Other than that is there a better method of distribution I should try out?


----------



## Kman10 (Sep 3, 2014)

Weigh in and out, can't guarantee same weight otherwise


----------



## Finley (Oct 19, 2014)

Same this morning, shot 1 @ 24 seconds, shot 2 @ 18 seconds. Measured tamp which was 17.2lb & 19.8lb so pretty close. Must be something wrong with my distribution as times are just so random? The MC2 is a bit of a pain to grind straight into the PF so will look into different methods. Any suggestions to start with?


----------



## Mrboots2u (May 10, 2013)

Finley said:


> Same this morning, shot 1 @ 24 seconds, shot 2 @ 18 seconds. Measured tamp which was 17.2lb & 19.8lb so pretty close. Must be something wrong with my distribution as times are just so random? The MC2 is a bit of a pain to grind straight into the PF so will look into different methods. Any suggestions to start with?


Id start with distribution being the cause ( channeling , dead spots )

Do you have a naked pf ?? What is the coffee you are using , how old is it? ( could be overly fresh playing with your shots )

Id would also advocate weighing in and weight out


----------



## Finley (Oct 19, 2014)

Yep using a naked PF at the moment, no spraying but can see that it will be a fast second shot as soon as the coffee starts coming through. Using week old hasbean IMM beans & I weigh in and out - 17g in 34g out at the moment.


----------



## Mrboots2u (May 10, 2013)

Your only grinding one dose at a time ? Not 34g in one go and halving for example (has been done before )


----------



## Dylan (Dec 5, 2011)

110deg(I'm assuming C) is much too high (If F then much too low)... if the water is at this temp it would spit and boil as it came out of the group. What type of thermometer do you have?

A typical routine on the Classic involves flushing water through the group until the boiler heating light comes on. Wait until it goes out again, then wait 'X' seconds (10-15ish from memory) then pull your shot. do this EXACTLY the same every time and your temperature will be (roughly) the same each time.

To improve distribution try grinding into a separate metal (metal helps disperse any static) container and shaking the grinds up a bit in there, then pop them into your PF.


----------



## Mrboots2u (May 10, 2013)

If the Op is getting a nice even extraction across both shots, then adding another step in , pots and all that , seems a little self defeating....and wasteful

Question is Why is the second shot running quicker ? ( doesn't sound like channeling from the description of the OP )


----------



## urbanbumpkin (Jan 30, 2013)

Is there any chance the op can video the shot prep and as well as the actual shot. (Don't feel daft, we're good bunch. Obviously you'll feel a [email protected] but we've all done it).









I'm with the others in suspecting channelling but it would be spraying everywhere is using a naked PF.

How soon after the first are you doing the 2nd shot.


----------



## Dylan (Dec 5, 2011)

Mrboots2u said:


> If the Op is getting a nice even extraction across both shots, then adding another step in , pots and all that , seems a little self defeating....and wasteful
> 
> Question is Why is the second shot running quicker ? ( doesn't sound like channeling from the description of the OP )


If the basket is not VST channeling may well be happening but not visible during extraction. The extra step is to try and eliminate distribution as a cause, if the same thing happens after trying it then it can be dropped.

Finley - Is the basket VST? can you get a video up of the extraction coming from the naked PF. When the extraction starts up are there dead spots or is it nice an even across the base of the basket?

Are you grinding both shots together or separately? Is it fresh beans into the grinder with no stale grinds to land in you PF from the previous day?


----------



## Mrboots2u (May 10, 2013)

Fair point , could be micro channeling , 5 seconds different same dose, same grind , i presumed you would be able to " see it " channel ....


----------



## jeebsy (May 5, 2013)

Dylan said:


> 110deg(I'm assuming C) is much too high (If F then much too low)... if the water is at this temp it would spit and boil as it came out of the group. What type of thermometer do you have?
> 
> A typical routine on the Classic involves flushing water through the group until the boiler heating light comes on. Wait until it goes out again, then wait 'X' seconds (10-15ish from memory) then pull your shot. do this EXACTLY the same every time and your temperature will be (roughly) the same each time.
> 
> To improve distribution try grinding into a separate metal (metal helps disperse any static) container and shaking the grinds up a bit in there, then pop them into your PF.


That's the temp on the outside of the boiler, not the water coming out. OP is just using it to ensure a consistent starting point I think


----------



## Finley (Oct 19, 2014)

Cheers guys, to answer some questions:

1) Yes only dosing for each shot not altogether

2) 110 degrees celsius is the boiler wall, seen in another video of someone using 2 thermometers (1 on the boiler wall & 1 at grouphead) - the boiler read 110C while the grouphead read 93/94C when running water through. Even if wrong shouldn't this still give consistent pours?

3) Roughly 3-5 minutes between shots with me pressing steam button on/off to try and maintain the temperature reading, always flush when removing PF

4) Basket is a double from happy donkey, every so often I will see a dead spot at the beginning but isn't around long. Always flush the grinder the day after with a few grams to remove old grinds

Will try and get a decent video sorted next time I use the machine, funny thing is I bought 1kg of Italian Job from rave to only use while getting used to the machine and had plenty of consistent results with it, it's only since switching to using hasbeans IMM coffee that I've struggled, can get through a 250g bag so quick when things aren't going right!









Really appreciate the help!


----------



## Dylan (Dec 5, 2011)

I did not know the temperature dropped from boiler to group in the Classic, so ignore my comment about temp being too high. Yes you should be able to achieve consistency with too high a temperature.

What kind of thermometer are you using? Just wondering as if its K-type you can use this to test the water temp as it exits the shower screen.

HD will just be a standard basket, a VST can be useful to analyse things like this, as it shows up channeling very clearly.

The roast from HasBean will likely be lighter than IJ from rave, and harder to get right. An MC2's grind is somewhat inconsistent, so will further struggle with a lighter roast, this all points toward distribution being your problem.

Experiment a lot with your distribution, as above try really mixing them about in a separate container. Also try 'WDT' which is poking a pin or two into the bottom of a cork and using this to distribute the grounds. Have a look here for a longer breakdown.


----------



## urbanbumpkin (Jan 30, 2013)

Finley said:


> 4) Basket is a double from happy donkey, every so often I will see a dead spot at the beginning but isn't around long. Always flush the grinder the day after with a few grams to remove old !


Just a long shot.....Are you doing a short flush in between shots to clear the group?


----------



## froggystyle (Oct 30, 2013)

Are you single dosing or is the hopper full of beans?


----------



## froggystyle (Oct 30, 2013)

Scratch that. Bloody tapatalk having a mare and just read previous posts.


----------



## Finley (Oct 19, 2014)

Will try other dosing techniques then, thanks for the link will have a read in the meantime







Didn't realise lighter roasts could cause some issues, may have to buy 1kg of something cheaper from hasbean to practise with. Yeah I do a quick flush after removing the portafilter, then hit steam to get temp back up a little. Would be easier to get a PID but keeps me more hands on for now


----------

