# First shot runs faster



## fluffles (Sep 4, 2012)

Hi,

I've been consistently finding that my first shot of a new bag of beans runs faster, is this a known thing?

When changing beans I usually grind until all the old stuff is gone. I then fill my tube hopper with the new beans and place a weight on top (as per normal for me). I quite often then find that the first shot is a gusher, so I go tighter. Then subsequent shots are chokers so I end up backing off and often end up at the same point I started at with the gusher.

Is there something about having a near-empty chamber that produces a coarser grind for that first shot?


----------



## h1udd (Sep 1, 2015)

are you weighing the beans after you ground them ?

if not, its likely the 1st shot is about 2-3g lighter due to retention filling up the space from the previously cleared out old bag.

try a quick purge on a new bag, just run 3g through the grinder to take up any retention slack and then go for the shots


----------



## Mrboots2u (May 10, 2013)

Your pulling each shot at the same reading on the pstat each time ?


----------



## DavecUK (Aug 6, 2013)

Just retention of old grounds in the grinder causing it.


----------



## fluffles (Sep 4, 2012)

h1udd said:


> are you weighing the beans after you ground them ?


yes I always weigh so it's the same weight.



Mrboots2u said:


> Your pulling each shot at the same reading on the pstat each time ?


Yep, always when the heating element light goes out.



DavecUK said:


> Just retention of old grounds in the grinder causing it.


Sorry I don't understand...


----------



## Mrboots2u (May 10, 2013)

When the light goes out - is the pstat reading the same each time ? At the top of the pressure


----------



## garydyke1 (Mar 9, 2011)

We always dump the first dose on the Mythos for this very reason when changing coffee.


----------



## GlennV (Mar 29, 2013)

fluffles said:


> Sorry I don't understand...


The chute will contain the coffee that was ground last when you were finishing up the previous beans. It will be coarser, as it didn't have a weight of beans above it when it was being ground.


----------



## fluffles (Sep 4, 2012)

Mrboots2u said:


> When the light goes out - is the pstat reading the same each time ? At the top of the pressure


I don't always look if I'm honest, but I've never known it go higher... why would it? If it was an issue with pstat then surely I would see these inconsistencies at other times and not just when changing coffees?


----------



## fluffles (Sep 4, 2012)

garydyke1 said:


> We always dump the first dose on the Mythos for this very reason when changing coffee.


That's interesting, maybe there's something in it. I'll try doing the same


----------



## fluffles (Sep 4, 2012)

GlennV said:


> The chute will contain the coffee that was ground last when you were finishing up the previous beans. It will be coarser, as it didn't have a weight of beans above it when it was being ground.


Hmm that's a good point. I can't remember whether I usually discard a small amount of the new beans.

It's possible that because the old coffee has stopped coming through that I assume it's all gone, but of course there will still be some stuck in the chute against the SCC flap thingy. I'll try clearing this manually by poking around.


----------

