Dose

Matt Whyard

I know baskets have been discussed at great length elsewhere, but I'm interested to hear what people think about running lower doses. I personally don't like huge amounts of espresso and as such am drawn to the VST 15g which should be fine for running doses between 14 and 16g.

Since the VST baskets are not tapered in any way, the puck has a very shallow depth and requires a very fine grind. Whilst I haven't done extensive tests yet, I seem to notice less even extractions (I think channelling) through the bottomless portafilter with these lower doses than with a higher dose in the 18g basket.

I know that some industry professionals run lower doses but they modify the flow rate on the their machines to reduce pressure. This is obviously not something we can do, so is a lower dose a good idea or is it making life difficult? Has anyone else observed anything similar or had different experiences?

Frans Goddijn

MattW post=10647 wrote: I seem to notice less even extractions (I think channelling) through the bottomless portafilter with these lower doses than with a higher dose in the 18g basket.

Is the 18g basket you refer to also a VST?

The VST's can reveal if your grinder setting is a little off or if your tamping can be improved upon, or if the beans are less well developed in the roast.

If you get channeling you could try stirring / redistributing the grinds in the basket right after grinding and before tamping. Or grinding the tiniest bit finer.

Reiss Gunson

with the L1 the lower the dose the easier it should be

bring the lever down a little more smoothly, i.e. so the seals gradually rise above the 4 inlet ports and that initial surge of water into the brew chamber isn't too violent, such that it washes out the puck

if as frans suggests you can provide a few more details about what you want to do i will try replicating it here; i.e. dose, basket, coffee being used, pre-infusion time - the more details the better

also, what grinder?

reiss.

Matt Whyard

Frans - yes I'm referring to VST 18g too. I'm very careful with my basket prep, getting it really level before a medium-firm tamp. i don't stir much as I never thought this would be necessary.

Reiss - grinder is ceado e37s. Using light roast single origin, VST 15g basket typically dosing 14.5g and pulling a 29g shot with 5 seconds pre-infusion followed by 35 second extraction. Tamping with the new style Londinium button tamper. The coffee appears around the edges towards the end of pre-infusion, when I release the lever the coffee starts to appear towards the centre of the basket too. Initial streams start to fall in 2 or 3 places around the edges (but not at the very far edges) and typically form a single stream after 10-15 seconds or so. If I remove the puck after extraction and look on the bottom I can see a handful of dark spots which I assume is where the water is exiting the puck (thereby leaving lots of lighter areas where the water is not exiting).

I'm interested to know why you think a lever should make smaller doses easier, what are the characteristics that make this so?

Reiss Gunson

easy. on the L1 you are pre-infusion with boiler pressure, so larger doses are more of a challenge to achieve complete pre-infusion with in a reasonable time

small doses are a dream in that you can reduce the pre-infusion time

i should be able to post you a video clip anyway, but I'm taken up wth keying invoices just now

if i don't get it done before we pull the site (tonight your time) i will get it up as soon as we come back up - we are finally powering up to the next level of website capability

reiss.

Frans Goddijn

MattW post=10650 wrote: Frans - yes I'm referring to VST 18g too. I'm very careful with my basket prep, getting it really level before a medium-firm tamp. i don't stir much as I never thought this would be necessary.

Let us know how it goes if you do redistribute/stir, loading 15g in the VST 15g basket and maybe grinding the tiniest bit finer. A "light roast" can mean many things but you might try a slightly higher dose too. If the flow comes out beautifully but a little fast, that is no problem as long as the shot tastes truly amazing.

Matt Whyard

Thanks for your comments - I am unlikely to get to try this until the weekend but I will endeavor to take a video clip when I do.

My instinct tells me going finer will not help as it is already quite a slow shot and it takes quite a few seconds before the first drop hits the cup (even after I release the lever).

Reiss Gunson

try nutating then, if you are not already doing so. this will effectively increase the tamping pressure around the perimeter, relative to the centre

so it's level off and sweep grounds out to the perimeter to fill any holes/gaps

then nutate

then a dead level tamp with just enough pressure to flatten the top (i.e. to remove the convex shape from the nutating)

reiss.

Reiss Gunson

another question - how fresh is your coffee? are you sure it isn't too fresh?

has your machine been on for an hour?/is it right up to temperature? (a lighter roast needs a higher brew temp, as you probably know)

is the lever grabbing at 45 degrees when you release it?

Matt Whyard

Reiss Gunson post=10655 wrote: another question - how fresh is your coffee? are you sure it isn't too fresh?

has your machine been on for an hour?/is it right up to temperature? (a lighter roast needs a higher brew temp, as you probably know)

is the lever grabbing at 45 degrees when you release it?

It's a couple of weeks old (maybe a bit more).
I always give the machine a good hour and a short flush.
I wouldn't say 45 degrees, probably a little bit higher but I think this has always been the case.

I will try and document/video clip as much of this as possible.

Reiss Gunson

hi matt

this is what i have;

31.55g brew weight delivered in 24s, excluding a pre-infusion of about 3s, from a 14.5g dose

i used a Compak E8 and a 15gVST basket, ridge less






i'm not sure there is too much to complain about with the puck, its not perfect, but its not too shabby either

Reiss Gunson

i will try and give it another go this afternoon, grinding a little finer for you to try and hit your 35s time

i am pretty fine already - def to the point where it is clumping

i thought it was pretty straight forward - that is my second attempt above - on my first attempt i left the grinder where i had it set for an 18g dose as it was my first shot of the day and i needed a baseline to determine how much finer i needed to go. as it turns out i didn't go quite fine enough, but i'll nail it next time

the L1 is absolutely perfect for this as you are pre-infusing at boiler pressure of 1.3 bar - i doubt the pump boys can get a pump to deliver at such low pressure, so i doubt its the L1 at issue

once the puck is saturated its all good, channelling isn't going to occur if the distribution is there

reiss.

Reiss Gunson

I've run another, slower one which i will post shortly. to my taste the bean tastes a bit strangled at this slower rate and i would think the optimum would lie between my previous attempt and this one

another thought has occurred to me, if your grinder is brand new how many kilos have you put through it? new burrs can do weird things which i am unable to explain from first principles, but by observation there is no denying that it occurs

Salvatore Taibi

Reiss Gunson post=10658 wrote:
the L1 is absolutely perfect for this as you are pre-infusing at boiler pressure of 1.3 bar - i doubt the pump boys can get a pump to deliver at such low pressure, so i doubt its the L1 at issue

reiss.

It certainly isn't the LI. My routine is to dose 14.0g in an IMS basket (I believe it's the B68 2T 24.5) using an HG-One. My target is 23-25g out in approximately 30s. I vary pre-infusion slightly, but stay within the 3-7s range. I believe, and this is just my opinion, that the group on the LI is designed for dosing 14g doubles or 7g singles.

I have always said the single shot (7-8g IN/12g OUT) is where the LI truly shines.

Reiss Gunson

take two. the pump makes a hideous racket because this machine is running the enhancement kit (new pump expected january), and happily the tank runs out of water at just the wrong moment, which is the alarm you can hear :pinch:

[video width=425 height=344 type=vimeo]149096999

this clip shows the removal of the PF from the group from the shot above, and an inspection of the puck. i can't see too much wrong with it

[video width=425 height=344 type=vimeo]149097329

Matt Whyard

Reiss - thanks for taking the time to do this. It's an obvious point but with the enhancement kit we are not really comparing like-for-like? Having said that what you were seeing was not that different to what i have seen. I guess the dark spots on the underside of the puck is nothing to worry about?

To answer your other question, my grinder has probably had 10kg through it.

I'll put a video up of my results at the weekend for comparison.

Reiss Gunson

you're right, its not like for like

your setup at 1.3 bar PI is more ideal for this particular task than mine running 2.8 bar PI!

the dark spots are where the water comes out; you are going to get that above each hole in the basket and if you've got slightly higher flow above a hole it is going to take slightly longer to dry out and will appear as a dark spot for a brief time after the puck is removed from the basket

i don't think you're going to do too much better than what I'm showing there, frans might have a more exacting view which i would be pleased to hear, but I'm reasonably happy with it. I'm sure its not WBC standard, but its perfectly serviceable

i think your grinder will perform better when it has had another 10-15Kg through it - i know my E8 really improved after 25Kg

taste wise have you tried easing it off slightly - how about 30g in 30s?

Frans Goddijn

I could set my line pressure for 1.3 bar and prepare an espresso from my ridgeless VST 15g basket.

If the puck is not showing holes from channeling, I do not worry about the looks and if the taste disappoints me I'd first look at other things before studying the puck.

Frans Goddijn

There you go, especially produced for Matt Whyard! The VIMEO version is still uploading. The very first attempt with a grind setting that I already had went fine so I will leave it like this for now. Matt, if you can post / specify exactly your work flow video, than we can compare more closely.

[video width=425 height=344 type=youtube]bht-U6s60dc

Frans Goddijn

VIMEO version:

[video width=425 height=344 type=vimeo]149133590

Salvatore Taibi

Thanks for the video, Frans. Is that how long you would normally let such a shot run? It's hard to tell from the video, but from what I can see I would've pulled it much sooner. Of course, I think our preferences are quite different.

Frans Goddijn

Salvatore Taibi post=10667 wrote: Thanks for the video, Frans.

Hope it helps Matt!

Salvatore Taibi post=10667 wrote: Is that how long you would normally let such a shot run?

I mostly aim for 30g but recently at BOCCA, a specialty cafe place in Amsterdam, former Dutch Champion Yakup Aydin (see below in a 2011 video snapshot preparing for WBC 2011 in Bogota) made us a longer shot and that was quite delicious so I experiment with that.

Salvatore Taibi

Thank you! Experimentation spices things up a bit, doesn't it!?!

Matt Whyard

Apologies I haven't got round to contributing the video I promised on this, but I never seem to have anyone around willing to video for me (kids around, hectic days, etc).

Anyway, I've been paying particular attention to this over the last few weeks and thought I'd share the conclusion I've come to.

I drink medium-light roast coffee. Light roasts generally require a finer grind in order to keep the shot in the ballpark 25-35s range. I think there's a tipping point such that when you go finer than this point you start to introduce channeling (I think this has been observed by many others - going finer increases extraction yield up to a point, then it starts to reduce).

With some light roasts you don't go past this post, but those which require a particularly fine grind then benefit from updosing slightly so that you can coarsen the grind to the point where this channeling doesn't become an issue. With darker roasts this isn't really an issue as your grind is already coarser. Similarly, for anyone already dosing in the 18g range then this is also probably not a concern.

For me, I like to drink quite short espresso shots (in terms of overall volume, not brew ratio). So a 14g dose into a 28g espresso is usually good for me. However, some coffees that need a really fine grind don't work well as a 14g dose and so I must increase dose slightly and coarsen the grind to get a nice even extraction.

Don't know whether this matches anyone else's experience, but that's my current thinking

Frans Goddijn

Thanks for sharing!

Last week a friend of mine (Jan van der Weel) and I attended an evening seminar where one of the speakers was Maxwell Colonna-Dashwood. He talkes about many things but what you say above was also discussed. A report is part of this blog:

http://kostverlorenvaart.blogspot.nl/2016/02/think-coffee-out-of-box.html

So grinding "finer" can be thought of in different ways.

Also, a while ago when Jan and I were sitting in as jury members in a national barista contest, we learned a lot from some remarks of fellow jury members, who were much more qualified than we. One young woman who has won several consecutive Latte Art championships, said that with a very good grinder, a fast flowing shot can be absolutely delicious. So it's maybe not always necessary to keep grinding finer to make a shot go as slow as you expected.

Matt Whyard

Hi Frans,

I know quicker shots can be good from EK43, can't say I've had a good one with my more conventional grinder though. Maybe I should experiment more - I do tend to rigidly stick to "the rules".

Matthew Hoffman

Matt, Much of what you say is in line with my understanding (a lot of that courtesy of Matt Perger). One thing, though; with a lever machine I don't believe it's necessary to stick to upper limits derived from pump machine timings. That is because the lever process naturally reduces pressure and temperature as the shot progresses, and therefore relatively little (compared to pump machines) is happening towards the back end of a shot.

Matt (there are three "Matts" in this post)