Can hot portafilter burn the coffee even before brewing? - Page 2

Beginner and pro baristas share tips and tricks for making espresso.
kramerica (original poster)

#11: Post by kramerica (original poster) »

malachi wrote:Unless there is something SERIOUSLY wrong with your machine, your portafilter should not be hot enough to burn your coffee.

Look at the portafilter/basket combo. There is actually a VERY limited amount of contact between the two - and good airspace around the basket.

I'd look at something more likely as the culprit (flush routine, dirty equipment, uneven extraction due to either distribution or grind quality, coffee quality).
I used to leave the basket in the portafilter, letting it heat up too. Like I said, problem completely solved by heating up only the portafilter w/o the basket, and inserting the basket only before grinding.

BTW, fixing that made me discover a problem of taste layers in the cup, as the bottom was more acidic than the top. That's probably due to temp drop during the shot. I managed to solve that problem too by turning on and off the "steam element" during the shot. I manage to even out the cold water input with the extra heat and by taste only I can tell that I'm doing it quite well since the layering is totally gone, no more bitter burnt flavour, no sour tone, just a balanced and tasty shot.

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malachi

#12: Post by malachi »

Perhaps Barry can chime in here - as he has some clear scientific data on temp transfer from portafilter to basket.

Suffice it to say that it is HIGHLY unlikely that this is the cause of your issues.

The challenge with espresso is that you're taking a subjective measurement of the product of myriad variables. So what you are describing as "burnt" might not actually be the result of temperature issues but could be roast of the beans, dirty equipment -- it could be what I might describe as "acrid" or "astringent" (in the green perhaps). I've seen folks describe what I think of as "sour" as "bitter."

I appreciate that you seem to have "solved" your issue - but I don't think that this is evidence that your diagnosis of the issue itself is accurate.
"Taste is the only morality." -- John Ruskin

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boar_d_laze

#13: Post by boar_d_laze »

The simplest fix might be to use lighter roasts.

It's fairly common in home and bar environments that, for whatever reason, the first cup of the day is bitter; while subsequent shots are not. At least that's been my experience and have heard this from others who are not online. Can I get an amen on this? So, simple fix no. 2 is just to pull a shorty and sink it. Or ... do what I do and use it to make a flavored latte for your unsuspecting mate.

The phenomenon does not seem to be [entirely] dependent on HX temp. My guess is that there are two factors at work. One: An absolutely clean basket performs differently from one which has been used. After the first shot, the portafilter basket loads up a bit and creates some back pressure. Two: After pushing a shot through an actual puck the temps from the HX coil through the group and portafilter find an equilibrium. Pure speculation only.

BDL

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malachi

#14: Post by malachi »

Occam's Razor...

Sounds like your first shot is at a higher brew temp. Logically... this would make sense with a home HX machine of course.
"Taste is the only morality." -- John Ruskin

Matthew Brinski

#15: Post by Matthew Brinski »

malachi wrote:Occam's Razor...
That pretty much sums it up. This thread reminds me of some ideas I had when I was early in my espresso making experience. I live at a relatively high altitude (8,500 ft.), and I blamed my elevation on problems I was having with bitterness, early blonding, and other problems. I convinced myself of "high altitude causes" such as the flash boiling of water above the coffee cake before it comes under pressure. I was convinced of certain phenomena, and I even posted about them extensively in the blog I had at the time. There are some minor altitude related issues, but for the most part, I was full of crap.

What I eventually realized was that I truly didn't understand espresso preparation. I knew how to follow what person "a" or person "b" said was the right way to make espresso, but I didn't actually get the whole process with its interdependent variables. What fixed my problems was getting back to the basics by adjusting and gaining an understanding of dosing, redistribution, flush routines, etc.

My intent is in no way to slam the the OP, but I'm pretty sure the heated basket isn't causing the problem.

kramerica (original poster)

#16: Post by kramerica (original poster) »

I understand and respect what you guys say, so I decided to test it the best way I can.

I made 4 consecutive shots trying to be as consistent as I can be, when the only variable was heating the basket vs not heating the basket. The pulling order was: Unheated - heated - unheated - heated.
After making the four shots I asked a friend to mix them so I wouldn't know which are the heated basket shot and which are the unheated. Two shots had a distinctive clear burnt smell and the others didn't. The friend concurred that the "burnt" shots was the heated basket shots. Although this is not a 100% proof blind test, when you sum it up with the consistent 8-10 good shots I had since not heating basket (not changing anything else) to me that's enough proof.

You also have to understand that the basket in the group head gets really hot. I can't even touch it for more than 1/2 sec. without getting a burn. I've always suspected that it may burn the coffee, and I proved to myself (even if you guys still don't "buy" it) that I was right.

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HB
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#17: Post by HB »

Matthew Brinski wrote:My intent is in no way to slam the the OP, but I'm pretty sure the heated basket isn't causing the problem.
kramerica wrote:Although this is not a 100% proof blind test, when you sum it up with the consistent 8-10 good shots I had since not heating basket (not changing anything else) to me that's enough proof.
I don't doubt your results, it's asserting the cause that gives me pause because your espresso machine's thermostat has a wider deadband than the effect you hope to measure. Years ago I did measure the temperature difference between the top and bottom of the puck for hot/cold baskets:



The distance between the lines indicates the cold/hot basket delta; the distance from the 0 axis represents the top/bottom delta. It shows that indeed cold/hot baskets do have a measurable effect on the first seconds of the delta between the top/bottom, but the effect falls below the boiler's natural temperature variance shortly thereafter (measured on a La Marzocco Linea without PID controller). That said, I don't consider the above chart the last word on the matter, as it was hastily created from just a few trials back in 2004 in response to a discussion on CoffeeGeek.
Dan Kehn

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boar_d_laze

#18: Post by boar_d_laze »

Problem? Solved, and that's a good thing. Stick with what works, I say.

Adequate explanation? Not so much, if I read the preceding posts correctly. I'm unhappy with the idea that the basket burns the fines, while the water itself doesn't. It doesn't make sense that the basket is significantly hotter than the brewing water, especially after the portafilter cum basket were tempered with a pre-brew, equilibrating "water dance." Although I suppose this could have something to do with differences between immersion and contact conduction. Quien sabe?

Occam's Razor has limited predictive utility. A right answer always appears a simpler after being shown right.

BDL

wildlyesoteric

#19: Post by wildlyesoteric »

'Q' wrote:Since my Expobar runs quite hot, one of the things I've been playing with is; after flushing and removing the portafilter, dipping it (the PF) in a container of warm water for just a second to cool it slightly. Then drying and filling. I've had some good results.
err, take it out before flushing? I never flush with the PF in the group.. always a pain in the ass to have it draining over your counter and grinder making a mess (after towel drying -- always possible to let the water drain out but it takes an extra few seconds).

wildlyesoteric

#20: Post by wildlyesoteric »

HB wrote:I don't doubt your results, it's asserting the cause that gives me pause because your espresso machine's thermostat has a wider deadband than the effect you hope to measure. Years ago I did measure the temperature difference between the top and bottom of the puck for hot/cold baskets:

<image>

The distance between the lines indicates the cold/hot basket delta; the distance from the 0 axis represents the top/bottom delta. It shows that indeed cold/hot baskets do have a measurable effect on the first seconds of the delta between the top/bottom, but the effect falls below the boiler's natural temperature variance shortly thereafter (measured on a La Marzocco Linea without PID controller). That said, I don't consider the above chart the last word on the matter, as it was hastily created from just a few trials back in 2004 in response to a discussion on CoffeeGeek.

OOH cool, it passes the hot one!