Post By Yelta
Post By Jackster
Post By deegee
Post By level3ninja
Post By knastoer
Grind times tamp equals brew pressure
Good people, could I ask for some input from you?
If the starting point is "medium grind, medium tamp", what can, in general, be expected of the changes in taste in the cup, if one goes "finer grind, lighter tamp" or "coarser grind, harder tamp" respectively?
Secondly, in your experience, what keeps the brew pressure more stable all the way through the shot, finer/lighter or coarser/harder?
Edit: The following was only meant as background information, not the focus of the thread, which is the above.
I've been having an issue with an undesired bitterness lately, it's a bean that I know quite well, and it's home roasted. In another thread, I've been complaining about poor crema, but that problem has become a lot better, unfortunately, I'm now having trouble with the taste. Damn...
Last edited by knastoer; 8th March 2019 at 05:02 PM.
Reason: To clarify intention of thread
Are you still using the bottomless PF Leo?
You say "it's a bean that I know quite well, and it's home roasted." tell us some more about the beans, type, how and when roasted, degree of roast, storage method etc, we cant help if we don't know specifics.
What machine and grinder are you using? I'm sure you have mentioned it previously, nothing in your profile to give us a clue.
Is this your first espresso setup?
Have you settled on a dose weight using the five cent test?
I also note you have started multiple threads on the same subject, doesn't make it easy for those trying to assist, much better for those trying to follow your progress if you stick to a single thread.
We're trying to help but without specifics and your questions being asked in multiple threads it's difficult.
Leo, make 3 drinks. Your usual, and 1 either side and taste compare. Maybe report back with your thoughts?
Hi Yelta, thanks again for your willingness to help. This time I wasn't, at least directly, out for help (which is the reason for the new thread). Instead, I was curious if there was any sort of consensus about how changes in grind/tamp while maintaining the same brew pressure affect the taste. Maybe somebody has even made scientific research in the area.
Originally Posted by Yelta
By the way, I've updated my profile with info about my set-up.
Hi Jackster, thanks for your reply. I was just hoping that maybe this had already been done in a more controlled and scientific way and on better equipment than what I'm able to. Will try to do some small-scale research sometime, though.
Originally Posted by Jackster
Using my old grinder that would not quite grind fine enough for a 2:1 extraction in 30 sec, was very little affected by tamp pressure. Even if I jumped on the tamper, it would only slightly affect extraction.
Conversely, at Christmas, my barista cousin was over. Making coffee for several of us. With my same grind, basket, and dose, and she wasn't tamping to the click on my espro tamper, also very little difference.
Very unscientific, and quite uncontrolled and small scale observations.... YMMV
G'day Leo, Once upon a time when I was new to all this, I had very similar questions, so here is my take on Grind, Tamp AND Dose :-
Originally Posted by knastoer
DOSE / GRIND / TAMP
Way back when I was a newbie, struggling pull consistent shots, I knew that grind, dose, and tamp were important. But I didn't fully understand that they must all be considered together - not separately - especially grind and dose !!!.
Here is what I thought back then :-
The grind is most important and is the major influence on the shot.
Tamping is important to get an even flow of water through the coffee.
The size of the dose will affect the strength of the shot.
At that time I thought that the flow rate was all about the grind and the tamp.
I didn't realise how much the dose also affected the flow of the shot.
My "lightbulb moment" came the day I read this :-
"One or two extra grams of coffee will have the same effect as a finer grind.
A gram or two less coffee will have the same effect as a coarser grind.
When the dose is increased, the grind needs to be coarser to compensate.
When the dose is decreased, then the grind needs to be set finer."
I had read many posts and articles about the importance of dialling in the right grind. But this one nailed down just how much dose & grind are inter-dependant on each other.
This is how I understand it now :-
A good extraction will only result from a correct combination of dose, grind, and tamp. All three must be considered together - most especially dose and grind.
The Dose :- The amount of beans by weight or volume that you choose to give the strength of flavour you want in the cup.
If you change it by more than a gram or so, you will need to change the grind to compensate.
You need to use a basket that will hold that dose so that the surface is just below the shower screen. (search 5 cent test)
The Grind :- Must be adjusted to get a good extraction with the dose that you have chosen to use.
The Tamp :- Is the least important of the three. Can be used to tweak the shot a little if necessary.
10 to 15 Kg pressure is typically recommended, but with the right dose/grind, it's more important to be consistent than to use an exact pressure. Small changes of dose or grind can be handled by tamping a little harder or softer.
If you want to delve deeper into this, have a look at this post on HB :-
They say it is "basic" info, but I think it's more advanced that that. I also think that you would need much better taste buds than mine to detect some of the changes they suggest, but mine are old and just about worn out.
The tamp largely only affects the amount of time it takes for the first drops to appear. If you time from the first drops shots with moderately different tamp pressure will all be roughly equal. You can of course tamp so hard as to have almost nothing come out, if you're putting more weight into the tamp than leaning on the bench you're wasting your time and effort.
DeeGee! You just might have passed that lightbulb on to me with your excellent post and the link, which also seems to make a lot of sense.
Originally Posted by deegee
Thanks very much!
Last edited by knastoer; 9th March 2019 at 02:57 AM.