# Newbie with another foolish question



## RobMo

I'm now a couple of days into ownership of a shiny Cellini and Mazzer mini E and have a question. I thought I'd put it here as ideally I'd like the views of other Rocket owners rather than generic answers. Bear in mind my entire experience has been acquired in the past 48 hours. I've consumed loads of caffeine and spend a load of time on-line so have probably managed to really confuse myself.

Generally it's going OK, espresso is pouring 2 x 1oz shots in about 25-30 seconds from the double PF (including a 3 second pre-infuse) with a reasonable looking crema from a 20g dose but they could do with a little bit more 'oomph'. I've got it in my head that 20g is already too much. Tamping is via an Espro (I have no idea what 30lb feels like and got an Espro to find out) and I'm fairly sure my tamping is reasonable for a novice (distribute the grounds, level, NSEW, 30lb tamp, polish). What I have noticed is the rate of flow from the PF is not absolutely consistent, no spluttering or random colour/texture changes but the rate of flow does seem to vary up and down a little during extraction, is this normal or am I getting channeling? The group manometer rises to 9bar a few seconds into the shot and holds it until the end, don't know if this is a useful measurement though. The mazzer is set at number 1 +1 notch on the calibaration dial and is dumping out just under 1g per second (22 seconds on the timer for 20g). I'm using the BB beans and an emergency purchase of decaf Peruvian from Waitrose (due to unnaceptable caffeine induced behaviour) at the moment but have a selection of beans on their way from Londinium and other reputable roasters so the results may change once I get something different to play with in the next few days. The Waitrose decaf is actually really nice, fruity and sweet, and works really well with milk, I prefer it to the BB beans. I'm religously abiding by the advice in the BB manual and in these forums regarding group temperature, so 30+ minute warm up then a big flush to drop the temperature in the group. I've not had anything sour or bitter so the routine appears to work, although my palate is still learning so these would probably be sink shots for many of you. Although I have loads to learn I think my current workflow is inexperienced but 'acceptable' but I recognise I'm at the bottom of a steep learning curve and happy to be corrected on any point. I've descibed it as best I can in case my problem is more to do with poor tecnique.

The question is should I be grinding finer or are the baskets really big for a reason and my volumes are low? Am I just trying to extract too much from a 20g dose? I think one of these needs to change but I'm uncertain which one it is. I've experimented already but my palate isn't in the right place yet so it's hard for me to say which way works best so would welcome views. The 20g dose on the current grind setting is sort of half way between the two changes in terms of taste. More grinds tastes better, finer grind tastes better but not sure which is actually 'better' if that makes sense. I know the beans aren't helping but I can see the finer grind/bigger dose question being something I'll encounter with premium beans so the advice is still relevant.

Many thanks

Rob


----------



## garydyke1

Volume is a poor method to measure liquid. If weighing your input then why not weigh your output? Then you can workout your ratio versus time and adjust from there.

Do you have an idea of what you want the espresso to taste like?


----------



## Glenn

It sounds like your on the right track. 48 hours is not enough time to be able to form opinions and get used to a whole new set of brewing variables.

If it tastes good then thats good.

You might not need to flush for as long as you are though.

Without seeing and tasting the espresso its hard to judge or advise.


----------



## RobMo

Hi Gary

I saw your post on weight rather than volumes on another thread but didn't fully understand the reasons. If you know the density of a fluid then weight or volume are just as reliable. I've assumed that coffee has a higher density than water due to suspended solids, so 1cc of espresso > 1g but I don't fully get the point on why weight is more critical than volume? To be honest I sort of get it, if the density of espresso is not constant, possibly due to the bean age, roasting process, extraction method (grind size, temperature and pressure) or bean variety then measuring by weight has validity in assessing the ability to transfer solids during extraction as a comparitor to a different bean, but this assumes that the flavour comes from only from the suspended solids? I would guess that flavour also comes from the oils which do not have the same taste characteristics or density as solids and may may appear in different proportions for each type of bean as oils evaporate and roasting and storage will have an impact on this. If oil and solids have different densities and appear in different proportions in different beans then weighing the finished espresso would not be able to determine the ratio of oil, water and solids and therefore the taste characteristics although it would be useful as a starting point (as would volume). I'm not sure why weight is more significant than volume, both methods appear flawed, but interested to find out. Sorry, probably can't apply an engineering background to making sense of this coffee malarkey and all information is good!

I guess I prefer espresso that's more ristretto style but I'm still finding my way. What I do know is that the current set up is OK but increasing the dose improves it and a finer grind also improves it but my palate isn't good enough to pick up the subtleties of each variation yet. Is grinding finer usually the prefered option to increasing the dose, or vice versa?

Rob


----------



## MichaelSmith81

As above, weigh your shots rather than use the volume. I use a 17g basket with my rocket and use anywhere between 17-18.5g of ground coffee. This yields (from experience) an approximate shot weight of anything between 26-36g in anything from 25-32 seconds, depending on the bean. Read the coffee discription to see if you are getting the taste notes as described, and the sour/bitter taste for under/over extracted coffee.

As for tamping pressure makes no difference, the main thing you should aim for is an even tamp, with even grind distribution in the basket before tamping.


----------



## RobMo

No, on reflection I don't get the weight thing at all.

I had assumed that the objective of weighing was to achive a 'golden ratio', so for 20g of grounds I should get 32g of espresso (or whatever it works out at) in approx 25 - 30 seconds, the only variable being time, although that would be constrained between upper and lower acceptable levels to prevent over or under extraction but have enough range to allow for small variations in temperature, grind and specific characteristics of the bean. But Michael's post says he gets between 26 and 36g output from a 17 to 18.5g dose. This gives a dose variance of 8.8% and an output variance of 38.4%, if the golden ratio is important, and by extension the quantity of solids transferred that create the difference in density, I don't understand why you would have such a difference between the input weight and output weight. If the equation is linear the variances should be the same. Not trying to be contentious, just want to understand the objective of weighing (other than to know how much something weighs) and why it's a better method than volume based measurement.

Just goes to prove that all newbies are fools! I suspect that there's already a post up answering this, had to ponder this one for a while.


----------



## Shady

Hi Robmo,

Like yourself I am a relative newbie to all this and have pretty much the same setup (Rocket evo Cellini & Mazzer mini e). I have been using caravan market blend and while initially I measured by volume (18g dose = 60ml in 25 to 30 seconds) I have more recently moved to weight ratios as prescribed here and found a significant improvement in taste.

Initially I used the"golden" radio of 1.6 (18g dose = approx 30g volumetric weight in approx 25 seconds) but have found the taste "truer" when I moved to a rate of approx 2.3 (18g dose = approx 42g volumetric weight in approx 25 seconds) - that is tasting closer to how it tasted in-house at Caravan.

As a newbie I am more than willing to be corrected but would suggest that you give this a try and see if taste improves.

Btw - in shifting to weight ratios I found myself grinding finer and getting out a little more than an ounce from a double shot (18g) instead of my previous 2 ounces.

Good luck and let me know how it goes.

Shady.


----------



## MichaelSmith81

I only use the shot weight as a baseline (ballpark figure) for the other variables, (Grind and Time). I adjust those two to get the taste I want and measure the weight for record purposes. I will then extract for a Shorter/Longer time to get Less/More weight. It's also useful for seeing how the beans change over time to see how the weight of shot extracted in a set time changes. At the end of the day every coffee bean is different, and the taste in cup is what we are all after. All the volumes/weights are only guidelines&#8230;.


----------



## big dan

I know this is a late response but I was browsing through the forums and I think I have a very basic answer to your question about weighing output rather then measuring volume. So here goes:

By measuring volume you are measuring the input and output as 2 different variables and it won't be as easy to manage changes in beans. By weighing the beans before and the weight of the shot after you can easily tweak the ratio to get better tasting coffee.

As an example I do 18g dose for a 32g output in 25-30 seconds. From my testing the volume is not always the same suggesting that the weight out can vary from bean to bean. There is also an argument that volume would also change accordingly but how easy is this to measure? If you have a coffee that tastes a bit sour and under extracted you can easily change the ratio to adapt:

Eg: 18g beans produces 30g in 25 seconds. So I adjust the ratio to 32g and I get 32g in 28 seconds and a much nicer shot. And it is still within my time range of 25-30 seconds. This is all done by having my espresso cup on a tared scale before I start extraction.

On the flip side of this example how easy would it be to measure the volume and adjust it? All I could do is let the shot run a little longer but this does not get me a benchmark or a setting I can use for future reference.

So n the above example I was using an initial ratio 1.6 (input x 1.6= desired yield) so I had 18 x 1.6= 30g shot. By adjusting this to 32g I got a new ratio of 1.77 (yield/input). So I now know for that particular bean it works best at a ratio of around 1.77. I write this down and now I have a list of different coffees and there ideal brew ratios! These can then be shared easily amongst the community and easily repeated by others.

Phew..... I hope that makes sense! I am not a super technical geek but I have been getting some of the best shots I have ever had from my Gaggia Classic using this method! Currently looking at upgrading to a rocket Giotto so will post more thoughts then! Hope this was of some help!


----------



## cruisecoffee

thank you for that


----------

