Flow rate for singles

Matthew Hoffman

I just used my new IMS single basket for the first time. It is rated for 12g, but I only used 9.2g, as that is what I had left of the beans (a mixture of Ethiopian and Guatemalan, roasted medium-dark). I had pulled a delicious shot with the same beans earlier in the afternoon, using 17g in a 28.5h IMS basket, at a rate of 1g per second for a total of 28 seconds.

At the same grinder setting as before, the 9.2g in the single basket came out at a little slower; I stopped the shot at 12g in 16 seconds. It was OK, but nothing special. Should I have ground finer/used more coffee to aim at say 14g in 28 seconds?

Matt

Kfir

I would use ~11g with this basket and grind finer in order to achieve 20ml in 22-23 seconds.

Also PI should be shorter than a double shot (less coffee to infuse).

Kfir.

Unknown

Matthew Hoffman post=7360 wrote: I just used my new IMS single basket for the first time. It is rated for 12g, but I only used 9.2g, as that is what I had left of the beans (a mixture of Ethiopian and Guatemalan, roasted medium-dark). I had pulled a delicious shot with the same beans earlier in the afternoon, using 17g in a 28.5h IMS basket, at a rate of 1g per second for a total of 28 seconds.

At the same grinder setting as before, the 9.2g in the single basket came out at a little slower; I stopped the shot at 12g in 16 seconds. It was OK, but nothing special. Should I have ground finer/used more coffee to aim at say 14g in 28 seconds?

Matt

Are you using an IMS "The Single" basket, or just an IMS single basket?

Matthew Hoffman

I'm using The Single, Stephen. Sorry that I wasn't clear about that.

Matt

Unknown

Matt, I dose that basket with 10.2g and use a curved tamper that fits tightly.

THE SINGLE that I use is a 23.5h in depth and that will have some effect on dose, especially if the shower screen is being contacted.

Matthew Hoffman

Well, I've made an interesting discovery. Although the IMS "SINGLE" that I have is rated for 12g on the box, it is only 22.5mm high and takes nowhere near that amount of coffee when used with the Londinium. The explanation is that I have a no. 1460302 (which is meant for the Nuova Simonelli - Faema - Rancilio machines; they must have a much higher dispersion screen than the Londinium). The equivalent SINGLE for the Londinium is no 1460309 (also 22.5mm) but rated for 8.5g - 10g. (I wonder whether they are identical baskets.)

I find that pulling a 9g shot (from 9g of coffee) for 18 seconds produces a very nice ristretto. The grind is, as advertised for the SINGLE, the same as I would use for an 18g shot with the same coffee.

Matt

Unknown

Matt, that was why I specified the h23.5 basket, and I still can only get about 10.3g into it without compacting on the Shower Screen.

I tried several IMS baskets and some work work in a range that was acceptable to me and my L-I and other would not because the headspace was to close resulting in much less than advertised grounds capacity.

You will find that ALL baskets will not take the "Advertised" grounds capacity and that is because of the headspace issue that the big commercial Lever Groups present to the basket.

The VST, IMS, HQ, and LaMarzocco baskets all work at lower doses because of the distance from the Group Gasket/basket rim to the bottom of the Group Shower Screen.

The IMS baskets have a height/distance number stamped onto the rim of the baskets for a reason and I believe it is safe to say that IMS does not do a good job of testing on the machines that use the commercial lever.

Matthew Hoffman

Thank you for that explanation, Stephen. Another thing I learned from fiddling with my SINGLE for a couple of days is that it seems to like a flow rate twice that of the double basket. In other words, if my favoured rate with my 17g basket for a particular coffee is 1g per second, I can only get a similar profile by grinding for 2g per second with the SINGLE. (I started out with a flow rate of 1g per second with the SINGLE, but the result was undrinkable.)

Reiss Gunson

hi matthew

um, I'm surprised by that tbh - that isn't consistent with my experience of using The Single

do get the biggest version though that stephen mentions, which i believe is sold as the 'LM' version - in the extensive thread on 'The Single' we set that out with all the product codes

if you are keeping the shot weight down to say 8g or something like that, i can't see why you would get in trouble with a flow rate of 1g/s (approx.)

in other words, i use this basket for ristrettos

can you step me through your process?

Matthew Hoffman

Reiss Gunson post=7448 wrote: hi matthew

um, I'm surprised by that tbh - that isn't consistent with my experience of using The Single

do get the biggest version though that stephen mentions, which i believe is sold as the 'LM' version - in the extensive thread on 'The Single' we set that out with all the product codes

if you are keeping the shot weight down to say 8g or something like that, i can't see why you would get in trouble with a flow rate of 1g/s (approx.)

in other words, i use this basket for ristrettos

can you step me through your process?

Here is what I did today. First, I pulled a shot with 17g of beans in an IMS 26.5 basket. The extraction timing was 25g of coffee in 28". Then, without changing the grind setting on my Pharos, I ground 8.5g of the same beans and put them in my 22.5 SINGLE. I then pulled 12g in the cup in 24". I conclude that the SINGLE, is designed to take roughly the same amount of total time to pull a shot as a double basket loaded with twice the weight. That sort of make sense as you would then expect to get the same taste profile in your single shot as in a double. Do other people get a different result? Is there anything wrong with my reasoning?

Reiss Gunson

I Hi Matt

I'd start by saying that you can like whatever you like, so if you prefer a flow rate of 2gps that's fine by me

But as far as 'rules' go, single baskets (all that I have used at least) are designed to have the same flow rate as a double (or triple)

This is achieved by reducing the surface area of the holes in the bottom of a basket

A quick visual inspection reveals that the diameter of the area on the bottom of the basket is greatly reduced on a single relative to the equivalent double from the same basket manufacture

A more detailed inspection reveals that the size shape and pattern/placement of the holes is also altered to achieve the manufacturers objectives for the basket in question

If you look to the IMS website they disclose all of these parameters, which will allow you to see there are significant differences between baskets that 'look' quite similar at first glance

Kind regards



Reiss

Matthew Hoffman

Thanks for your reply, Reiss. I think I misdescribed my "IMS Single" flow rate in an earlier post. It is not 2g per second, but 2 seconds per gram. So, 8 grams in basket; 2 seconds preinfusion; 16 seconds pull; 8 grams in the cup. (Or if I don't want a ristretto: 24 seconds pull and 12 grams in the cup.) I accept that this is not in accordance with the "rules", but I like the result.

Best, Matt