Anti-spurt tamping techniques

#1: Post by **ryanjg11** » June 24th, 2014, 7:43 pm

Using an HG One and GS/3 with a bottomless PF, I still get occasional spurting and it's usually with medium-roast beans. I've noticed the GS/3 is much more forgiving than my previous Andreja Premium, which would spurt all the time, no matter the bean.

I'm dosing to 18.5g, using the Espro calibrated tamper to ensure a good 30 pounds of pressure, and I'm quite sure the grind is dialed in because I have the right volume at 25 seconds. So, I really think it comes down to improving my tamping technique.

The HG One produces some really nice fluffy grinds and no real clumping, and all I really do is use a frog dissection needle to stir up the top portion (to remove the "inverse donut shape" that the HG One produces). I'm using the stock LM portafilter (I believe it's a triple basket), and so the untamped grinds never actually protrude above the rim of the PF.

Then, I'll just tamp that directly down to 30 pounds and give it some polishing spins. I've experimented with a half-tamp, knock, and then full-tamp, but this seems to actually create more spurting.

Just wondering if their are some new anti-spurt tamping techniques I could employ?

#2: Post by **kwantfm** » June 24th, 2014, 8:02 pm

I found that stirring the whole lot of grounds made a significant difference to me. I use a mini whisk and actually use a whisking motion.

#3: Post by ds » June 24th, 2014, 8:10 pm

Nutate.

#4: Post by **another_jim** » June 24th, 2014, 8:44 pm

There are no anti-spurting tamping techniques; it's way too late by the time you tamp. Preventing channleing is done by distributing the coffee in the basket so that the edges are sealed, there are no cracks, and the density is fairly even. Nutation works OK for this; the really heavy, can't fail, artillery is the Weiss Distribution Technique (WDT)

http://users.rcn.com/erics/ · #5: Post by **erics** » June 24th, 2014, 9:12 pm

I second Jim's comments. Have you watched this? Newbie Introduction to Espresso - Barista Mechanics [video]

For years upon years, I have ground into a spare cappy cup and used the WDT to "fluff up" the grounds like scrambled eggs. Is this step necessary? - I could care less. I then spoon the grounds into a basket resting on a tared scale and distribute NSEW, NSEW, and then like the tone arm on a turntable.

I have a pretty good looking distribution prior to tamping. My tamp has an unintentional mini-nutation using my thumb and fore finger on the tamper to ensure level.

#6: Post by **drgary** » June 24th, 2014, 11:47 pm

Sometimes these issues disappear with more headroom. Have you tried reducing the dose?

#7: Post by **erik82** » June 25th, 2014, 2:04 am

Using a small whisk did the trick for me with the HG One. The grinds really need a good stir from top to bottom.

#8: Post by **weebit_nutty** » June 25th, 2014, 2:46 am

It's all in the grind...

#9: Post by **cannonfodder** » June 25th, 2014, 7:18 am

Everyone gets them now and then and if they say they dont they are lying. There are a lot of things that can play into it. Quality of grind, quality (evenness) of distribution, dose, headspace, preinfusion, pressure ramp, blend of coffee, roast of coffee, origin of coffee.....

If you use a high grown hard bean with a light roast, you could be prone to a spritz. The density of the bean (in my opinion and observation) may produce fewer fines which act as sand in a bucket of gravel. They help fill those little air pockets around the aggregate and slow the flow of water through the coffee bed. A more brittle bean from a lower grown tree/varietal or darker roast, would have a tendency to fracture easier and produce more dust 'fines'. Those fines will help a puck self heal as the fines pack tight between the aggregate during the infusion and possibly help seal spritz's as they migrate to point of highest flow through the puck. No scientific studies or structured testing, just observation over many years.