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First few shots perfect, then all shots run too fast

5.1K views 21 replies 6 participants last post by  oursus  
#1 ·
Hi all,

I found some a really nice blend from Coffee-compass (Gusto Gold) which I have been using for a couple of days now (I use them 4 days from Roasted)

So..

1) following my usual procedure i pulled a double shot and it came out perfectly

2) Once the boiler got back up to the correct temp (104) I pulled another double shot (following the exact same procedure- Same beans, grind, dose, tamp, temp etc) and it came out perfectly

3) all good right

4) Then i did step two again, but this time the shot run way too quickly, it wasn't even gloopy and looked like there wasnt any resistance in the puck.

5) I adjusted the grind a notch or two finer (in case the beans have been affected in some way by humidity), but it still ran super quick. I'm talking a double shot (30ml) in 10 seconds as opposed to 30ml in 27 seconds.

After that I could not get it to run slow again. Is it because the machine got too hot possibly?

Before pulling any shot, I leave my machine to pre-heat for 40min then run some water out. Then leave the PID to get to it back up to 104.

I ran a shot this morning and it was better but a bit slow (although its better then it just pouring out.) and for this shot I did set the grind back to what it was in step 1 which was at 1E (Vario)

I have an ESPRO VST calibrated tamper by the way so I'm being constant in that area and PID is managing the temp.

Any ideas?

Thanks
 
#7 · (Edited by Moderator)
As @Mrboots2u says Coffee in the chamber/chute of the vario does need to be cleared when adjusting, or you are dealing with 2 grind settings in one shot & on the next shot the variance will increase if you've adjusted again. It won't be a huge factor on the vario, but still needs to be ruled out. Are you using pre-infusion, or is that still out of action?

The beans may be a bit young at 4 days, a heavily tamped dose, with distribution a bit off, combined with beans not behaving quite as young as they were 48hrs previously & pre-infusion turned off could quite easily create a gusher.

As the man says, weigh in, weigh out, clear the chamber when adjusting.
 
#8 ·
oursus said:
Sounds like a fracture puck to me..."better but a bit slow" Is this the first time using VSTs, if so what tamper & distribution are you using?

Did Jan get back to you about he PID @mem?
Hi Oursus

I will update the other thread regarding the PID question.

Regarding the VST's, no it's not the first time. I have a 15g and 18g VST. I use the 15g really and dose about 16g/17g in it. when using the 18g basket, I dose 19g

I am using a ESPRO VST calibrated tamper. What do you mean by distribution?

Thanks
 
#9 ·
mem said:
Hi Oursus

I will update the other thread regarding the PID question.

Regarding the VST's, no it's not the first time. I have a 15g and 18g VST. I use the 15g really and dose about 16g/17g in it. when using the 18g basket, I dose 19g

I am using a ESPRO VST calibrated tamper. What do you mean by distribution?

Thanks
Hi,

Sorry, that was supposed to read tamp, not tamper, you mentioned the tool in the original post... Distribution is just that, how you distribute the coffee in the filter, if uneven, when you tamp, you can be creating areas of uneven density in the puck...

Without sweating it too much, as boots says: weigh in, distribute evenly, tamp level (& consistently) weigh out.

If you're adjusting your grind, then empty out any grinds from the previous setting, or you're chasing your tail.

I only really use 18g VSTs - I dose 18g, all the time.

The other thing to mention is the beans, they may be a little young still...
 
#10 ·
oursus said:
Sounds like a fracture puck to me..."better but a bit slow" Is this the first time using VSTs, if so what tamper & distribution are you using?
You know what. I did look closeyl at the puck one time and i did see a slight crack. But checked others they didn't have it. What am i doing wrong?

My tamping method is:

- Dose from my vario for 12.5 seconds (produces around 16g of coffee)

- use my finger to move it around and level off

- apply tamper applying 5lb possibly of force just to get right then apply 30lb (Calibrated)

- twist then take off

I dont knock the side or tap the portafilter
 
#11 · (Edited by Moderator)
oursus said:
As @Mrboots2u says Coffee in the chamber/chute of the vario does need to be cleared when adjusting, or you are dealing with 2 grind settings in one shot & on the next shot the variance will increase if you've adjusted again. It won't be a huge factor on the vario, but still needs to be ruled out. Are you using pre-infusion, or is that still out of action?

The beans may be a bit young at 4 days, a heavily tamped dose, with distribution a bit off, combined with beans not behaving quite as young as they were 48hrs previously & pre-infusion turned off could quite easily create a gusher.

As the man says, weigh in, weigh out, clear the chamber when adjusting.
Yeah I am adjusting the Vario (Only on the LEFT side- say from E to D) while there are beans in the hopper, but when doing this I grind and throw away a few seconds worth before grinding into the basket.

Are you saying this is still wrong?

Yes, I am using pre-infusion. 2 seconds run then 6 seconds wait.

Thanks for all the help by the way guys
 
#13 ·
mem said:
Yeah I am adjusting the Vario (Only on the LEFT side- say from E to D) while there are beans in the hopper, but when doing this I grind and throw away a few seconds worth before grinding into the basket.

Are you saying this is still wrong?

Yes, I am using pre-infusion. 2 seconds run then 6 seconds wait.

Thanks for all the help by the way guys
That sounds fine to me, as long as you've even distribution & level bed.

For the gusher, I would only pay attention if it happens more than once (more than likely a combination of factors, basically a puck breaks for the same reasons anything else does, along a weak point, just like anything else)

As long as you're clearing the chamber, as you are, follow boots' process & you should be fine...

Is the 2s long enough for the pre-infusion? Perhaps @Mrboots2u @coffeechap & anyone with more lever/ preinfusion experience can weigh in here, I was just going for the first drop through the puck, then pause for a bloom...
 
#17 ·
mem said:
I did think it this could have possibly been it. Is this possible then- on a grinder of this quality?
As Boots says it's likely retention, I'd be inclined to purge 2-3G of beans at a new grind setting before grinding for a shot.

The Vario doesn't have the most powerful motor and guaranteed you'll be grinding around the 20 second mark which will induce some heat.

Though I'm inclined to believe the ceramic burrs may not suffer as badly than steel in the heat department.
 
#18 ·
Beanosaurus said:
As Boots says it's likely retention, I'd be inclined to purge 2-3G of beans at a new grind setting before grinding for a shot.

The Vario doesn't have the most powerful motor and guaranteed you'll be grinding around the 20 second mark which will induce some heat.

Though I'm inclined to believe the ceramic burrs may not suffer as badly than steel in the heat department.
Thanks. I grind for 12.5 seconds and I do purge around 2-3 grams when adjusting.

So yes, possibly the burrs must have got pretty hot after me making making 4 consecutive double shots.
 
#19 ·
mem said:
Thanks. I grind for 12.5 seconds and I do purge around 2-3 grams when adjusting.

So yes, possibly the burrs must have got pretty hot after me making making 4 consecutive double shots.
Sorry I meant to say around 10 seconds, I was thinking of the Rancilio Rocky I once had.

As others have mentioned, distribution of grinds in the basket is key for consistency along with weigh doses in and out,

shot time is relational but not the overall arbiter over whether a shot will be well extracted and therefore tasty.
:)
 
#20 ·
Mrboots2u said:
Pidded Silvia pre infusion isn't quite the same as other pump or lever machines ( pid is just turning pump on ? ) I would think its having nominal effect
There's a second setting, varying the voltage on the pump, so you can ramp that down or up over a set period...
 
#21 · (Edited by Moderator)
Beanosaurus said:
As Boots says it's likely retention, I'd be inclined to purge 2-3G of beans at a new grind setting before grinding for a shot.

The Vario doesn't have the most powerful motor and guaranteed you'll be grinding around the 20 second mark which will induce some heat.

Though I'm inclined to believe the ceramic burrs may not suffer as badly than steel in the heat department.
Would you say ceramic ones are always a better choice?