What is the problem when we overdose a filter basket?

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kwongheng
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#1: Post by kwongheng »

Hi all,

I have an expobar leva with a standard 2 spout portafilter from expobar. According to the distributor, the double filter basket is only rated for 14 grams. However, I have been dosing 18 to 20 grams on them, plus the puck gets an impression from the shower screen. The main reason I am dosing 18-20 grams is that most of the specialty coffee recipe calls for 18-20 grams.

Is it okay to cotinue overdosing with this filter basket? Recently, I am getting weird consistency problems such as grinding finer will increase flow rate instead of slowing it down. Is this common when overdosing a filter basket?

Kelvin

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redbone
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#2: Post by redbone »

Overfilling the basket does not allow for puck expansion during initial water contact with the grinds. Jamming the group screen makes for a messy group head and screen, stifles even water dispersion from screen, increases frequency of back-flushing, increases chance of back-flow into group, places stress on three-way valve as well as pump and piston seals, forces user to use a coarser grind, tamp with less pressure changing contact and extraction parameters and ratios ultimately changing quality of coffee in cup.

Or if you have a lever machine or machine without 3 way valve a large piston sneeze and mess. Trust me on this one. :|
Between order and chaos there is espresso.
Semper discens.


Rob
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HB
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#3: Post by HB »

kwongheng, Please don't cross-post to HB; Why is cross-posting strongly discouraged? provides the rationale for this site's policy. Contributors to this thread may wish to refer to this post to avoid needlessly repeating previous suggestions/comments. With that administrivia out of the way...
kwongheng wrote:The main reason I am dosing 18-20 grams is that most of the specialty coffee recipe calls for 18-20 grams.
The dosing varies greatly depending on equipment. You should treat "recipes" as a starting point only. Espresso 101: How to Adjust Dose and Grind Setting by Taste explains how to dial in by taste. That said, some machines and baskets are finicky about precise adherence to dose, others are not. In my experience, the typical stock Faema-style baskets work well at 14-17 grams. With VST baskets, stick closely to the recommended dose, otherwise they will channel more.
kwongheng wrote:Recently, I am getting weird consistency problems such as grinding finer will increase flow rate instead of slowing it down. Is this common when overdosing a filter basket?
It sounds like channeling. If you don't have a bottomless portafilter, I recommend getting or making one.
Dan Kehn

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cannonfodder
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#4: Post by cannonfodder »

Some machines are also very sensitive to headspace (air between the puck and shower screen) due to the design of the grouphead. I down dose 18-19 gram in a 21 gram basket just for that reason. Baskets are inexpensive, it is hand to have a few different sizes around.
Dave Stephens

kwongheng (original poster)
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#5: Post by kwongheng (original poster) »

Hi all,

Thanks for the reply, sorry about that cross-posting thing, I always thought the audiences are different which is why there are different forums, like different parties ... :P

Will bare that in mind.

kwongheng (original poster)
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#6: Post by kwongheng (original poster) »

looks like it more than just dosing issue, even with the correct dose I am getting very fast flow and its confirmed that one the parts in my grinder is broken... sigh,, again

dilin
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#7: Post by dilin »

The upper burr tab in your Baratza? Are you changing the grind without running the motor?