bobbin Senior Member Joined: 6 May 2006 Posts: 24 Location: london Expertise: Just starting
Espresso: Gaggia Classic Grinder: Ascaso
Posted Fri Mar 14, 2014, 8:54am Subject: Tamping and PRessure
So, the standard line is that you use about 30lbs of pressure when tamping. But this obviously depends on the grind. What is the difference between tamping lightly with a fine grind and tamping heavily with a coarser grind - as long as the shot time is 25 seconds or so - does it matter?
SStones Senior Member Joined: 24 Nov 2012 Posts: 518 Location: Canada Expertise: Professional
Espresso: Giga 5, ECM Giotto, Rocket... Grinder: Anfim Milano-Best Vac Pot: No :( Drip: Some $30 thing from Walmart Roaster: I buy pre-roasted.
Posted Fri Mar 14, 2014, 4:17pm Subject: Re: Tamping and PRessure
Well, yes. The amount of time it takes the flowing water to fully penetrate a coarse grind to extract the hydrocarbons is obviously greater than the time to soak a talcum powder-like ground. So... obviously, the finer the grind, the faster it can be extracted, but of course, the finer the grind, the more obstruction the puck will make against the flow. Hence the 24 second suggestion that new experimentors are given to work around provided they have a stock-sized portafilter and relief pressure. Tamping, on the other hand, has very little overall effect on the finished product. If you don't tamp, the grounds are a mess and won't extract well. If you tamp far too lightly, the puck won't slow the water from flashing through to boil and you'll end up with a bitter, burnt espresso. If you tamp too hard, even at a perfect grind, you'll get a very slight difference to the flow time, but hardly noticeable. What's important is the grind. The differences that tamping makes are nothing compared to having a perfect, consistant grind.
Posted Fri Mar 14, 2014, 4:34pm Subject: Re: Tamping and PRessure
If you use a very fine grind that REQUIRES a light tamp (say, 5 to 10 pounds), you will likely have an over-extracted flavor; "In your face" as it is called. If you grind coarsely and find it requires a very heavy tamp (say 75-85 pounds), you will likely find that you have a somewhat under-extracted cup which is light in body and flavor.
I have found that, with the correct grind (or close to it anyway), that you can tamp at 30 or like a gorilla and it doesn't matter.
There are exceptions; pressurized portafilters, lever machines, and grinders that create a very fluffy, narrow particle-size range tend to be more specific about the tamp that creates the best espresso. So as I have said many times, if you find you must have a very light or very heavy tamp, you are likely compensating for other factors which should be addressed, and dealt with if possible.
For someone who has had plenty of experience in the real world on this matter, tamping technique can (and does in my case ) have a huge impact on the end result... I think the above statement marginalizes the importance of good tamping technique.
Yes we all know how important grind consistency, but let's not lose sight of reality here. ... Poor tamping can destroy pretty much any shot regardless of how good the grind is. I think perhaps the above assertion is that you can easily correct poor tamping technique whereas it is much harder if not impossible to correct extraction issues stemming from a cheap grinder.
Let me add another point that hasn't been made: some machines are more forgiving than others when it comes to differences in tamping pressure. I have seen demonstrations of untamped pulls producing shots not too different from a tamper shot using the same high quality grind). I won't go into theories as to how this happens but I can tell you in my experience, both on my LCM pump machine and Cremina lever machine that unless I tamp it correctly the shots will be completely... Shot :) and down the drain they go.
calblacksmith Moderator Joined: 25 Nov 2007 Posts: 8,259 Location: Riverside, Ca, U.S.A. Expertise: I live coffee
Espresso: ECM Vene. A1, La Cimbali M32 Grinder: Azkoyen Capriccio, Major Vac Pot: 40s era Silex Drip: Msl. Com. brewers Roaster: gave it a try, decided no
Posted Sat Mar 15, 2014, 6:38pm Subject: Re: Tamping and PRessure
The whole point of tamping is to compress the puck to avoid channeling. The pressure you use does not matter near as much as being consstent. Adjust the grind to change the time of the shot. Once you get in the ball park with the guidline numbers then adjust for taste. Only change one thing at a time. The tamp is the least important part of the process
You can never come close to the pressure on the puck that the water puts on it. Be consistent and adjust the shots with the grind.
In real life, my name is Wayne P. Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!
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Posted Sat Mar 15, 2014, 7:27pm Subject: Re: Tamping and PRessure
Let's not make tamping sound like precision machining.
The basics of Tamping Technique: - Keep the tamper level and insert gently into the portafilter, on top of the coffee - With control, and while slowly increasing a downward force, press down hard, keeping rule #1 in mind. - When tamper stops compressing *1, lift tamper out of basket *2 - Without tapping on the portafilter nor banging it on the group, lock in place and make espresso. - Adjust grind to taste, then, if necessary, adjust tamp force to grind if necessary.
*1 within reason; feet should still be on the floor. *2 note that "spinning" the tamper is not recommended. If I wanted to see a floor show, I'd go to Vegas.
That should cover it, and with a bit of humor as a bonus, The humor is yours to keep, with our thanks, even if you decide to return this post.
We could talk about nuances of how to "properly" hold the tamper, what shape surface it should have, finding one that fits your hand, etc. And really, even there, use one that fits in your hand comfortably and allows you to maintain control.
I know of a respected, pro barista about the size and mass of an NFL lineman - he recommends and uses the "Handstand Tamp" technique.
bobbin Senior Member Joined: 6 May 2006 Posts: 24 Location: london Expertise: Just starting
Espresso: Gaggia Classic Grinder: Ascaso
Posted Mon Mar 17, 2014, 4:07am Subject: Re: Tamping and PRessure
Thanks for your imput. My question was prompted by something I read about the practice in Italy being to tamp lightly and grind finer. Whether or not this is accurate, I was wondering what the difference in quality would be between two shots of, say, around 25 seconds, one using the coarser grind tamped hard, the other with the finer tamped lighter. at the moment I'm doing the former (with a Gaggia Classic and Ascaso grinder) and getting good results - but there is of course always room for improvement.
takeshi Senior Member Joined: 12 Oct 2002 Posts: 1,061 Location: Houston Expertise: I live coffee
Espresso: Alex Duetto 3.0 Grinder: Super Jolly Roaster: Amaya Roasting
Posted Mon Mar 17, 2014, 7:52am Subject: Re: Tamping and PRessure
Whether or not this is accurate, I was wondering what the difference in quality would be between two shots of, say, around 25 seconds, one using the coarser grind tamped hard, the other with the finer tamped lighter.
It's been awhile since I've been in Italy, but fifteen years ago it seemed like most baristas were "up tamping," that is pushing the puck up against the tamper mounted on the front of the grinder. The net result is a fairly light tamp, because otherwise the barista would push the grinder over.
But note that as a rule Italians also dose much lighter -- which probably has a lot more to do with how fine they grind than how lightly they tamp.
For the little it's worth, I tamped that way myself for twenty years and thought it worked pretty well until I got a naked pf and SAW the consequences of the inevitable poor edge seal and bad leveling.
Whether or not this is accurate, I was wondering what the difference in quality would be between two shots of, say, around 25 seconds, one using the coarser grind tamped hard, the other with the finer tamped lighter. at the moment I'm doing the former (with a Gaggia Classic and Ascaso grinder) and getting good results - but there is of course always room for improvement.
The answer is a big, "It depends."
It depends on a lot of things -- including the fluffiness of the grind, the lack of clumping, the quality of your puck making skills, etc.
There's a limit to how much difference a powerful tamp can make in terms of flow rate with a fairly coarse grind. Once the puck is fully saturated and the pump fully engaged things tend to equal out for any tamp pressure.
I'm currently going back and forth between two tampers (18g Strada baskets, naked pf). One is a very heavy Brass Handle Espresso Coffee Tamper from Coffee Complements and it encourages moderate (at least) pressure. The other, a Butterfly Tamper, encourages more of a consolidation technique with -- at most -- very light pressure. Using the same grind, I find that I get similar flow rates with either tamper.
If I don't "polish" the puck surface, which Randy dismissed as "spinning the tamper," I have to do something else -- like "nutation" or "NESW" -- to make sure that pressure was evenly distributed around the edges. In my experience, polishing is the easiest and best way with a tight fitting tamper (such as a 52.35mm, VST/Strada specialty size). Using very light pressure while "polishing" makes a positive difference with a technique which relies more on "consolidation" than on pressure. It may not be much more than habit with my heavier tampers, but it's a necessity with the Butterfly.
Randy doesn't think polishing is important, I do, and neither of us is wrong.
Bottom Line As long as the coffee is evenly distributed in the basket, without voids or lumps, you don't really need much more pressure than is necessary to the level the surface; that's "consolidation." If your grinder and/or distribution is imperfect and you can use pressure to solve a lot of problems. But there are limits either way. The best consolidation technique (or, at least, my best technique) requires some pressure to fill in minor voids and homogenize distribution; while the strongest press won't fix rock hard lumps and bad distribution.
It's a funny thing. There are all sorts of right ways to tamp, and all sorts of wrong ways. What works for one person might not work for another.
Even the best grinder doesn't eliminate the need for competent puck building skills; and tamping -- while not as difficult as those required to "dial in" grind, dose and temp -- is one which needs to be mastered. Playing with your food is fun, so fool around with lots of styles and tampers and find which suit you best.
Posted Mon Mar 17, 2014, 11:04am Subject: Re: Tamping and PRessure
If I don't "polish" the puck surface, which Randy dismissed as "spinning the tamper," I have to do something else -- like "nutation" or "NESW" -- to make sure that pressure was evenly distributed around the edges. In my experience, polishing is the easiest and best way with a tight fitting tamper (such as a 52.35mm, VST/Strada specialty size). Using very light pressure while "polishing" makes a positive difference with a technique which relies more on "consolidation" than on pressure. It may not be much more than habit with my heavier tampers, but it's a necessity with the Butterfly. Randy doesn't think polishing is important, I do, and neither of us is wrong.
In THIS video, James Hoffman at 18:11 talks about nonsense techniques. Shortly after that time point he asks the audience, "Who polishes when they tamp?" And a number of people in the audience raise their hand. And he then asks, "Why do we do that two or three hundred times a day?" An audience member calls out, "Because it looks cool, Man!" James replies, "That's why I do it."
That entire video is definitely worth the 49 minutes. An educational watch.
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