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Why should I care about blonding?

Postby kmills on Mon Sep 17, 2012 3:07 pm

Barring any extraction problems visible with a naked PF, do I need to look for blonding if I brew to a set extraction ratio in a given time? I feel like watching for blonding just confuses the issue of finding the points in the extraction space for a given coffee that you like.

Stopping because you see blonding will stop you from hitting your predetermined brew parameters. Once you pick your locations in the extraction space, the blonding point becomes a non-variable dictated by dose, shot volume, shot time, and grind size (the real variables).

Did I answer my own question?
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Postby mitch236 on Mon Sep 17, 2012 5:32 pm

I don't watch for blonding any more. I pull the shot based completely on weight parameters. For example, if I grind 18 gm of coffee and want a 67% ratio, I would stop the shot at 27 gm (actually, I stop the shot a few gm short of the goal since the espresso keeps flowing for a few grams after the pump is cut).
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Postby GVDub on Mon Sep 17, 2012 5:55 pm

What we all should care about, in the end, is the taste in the cup. If you like what you're getting, it doesn't matter.

If, on the other hand, you find that the bitter elements that blonding tends to indicate are muddying the flavor in your cup, you should probably pay attention to it.

Blindly extracting to a set of mathematically determined parameters, be it weight, volume, time, or whatever else you may choose, is to serve the point of developing consistency in the cup. Once you let the parameters start overriding what you taste, that's what you should care about.
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Postby Peppersass on Mon Sep 17, 2012 7:06 pm

Like Mitch, I pull to a target brew ratio. But I also agree with George that you can't just do that.

In my opinion, and that of others, watching for the "blonding point" is not a reliable methodology for determining when to cut off the shot. The so-called blonding color is a difficult thing to describe, and can vary depending on the coffee and preparation technique/equipment. Further, opinions vary on where the exact blonding point occurs. Opinions also vary on the effects of cutting off the shot before or after that point. Many people have reported that shots taste better when they are allowed to run past the blonding point, and I'm sure there are others who have had exactly the opposite experience when they've cut off a shot early or when they think the shot has gone blond.

Sure, you know when the flow is very dark that the shot hasn't run long enough, and there's an obvious point at which the flow turns very light and you know that you're past optimum extraction and are entering the realm of over extraction. But we're not talking about obvious extraction flaws. We're talking about where to cut off the shot when it has reached the range of acceptable extraction, say in the window of about 18%-22% extraction yield.

Mitch and I, and a lot of others on this board, have found that it's more reliable to pull to a particular brew ratio. The target beverage weight and the time it takes to get there are easy to repeat. The technique is to pull that brew ratio and, as George says, taste the result (and, as Mitch and I might do, test it with a VST refractometer.) If the brew tastes like you think it should, or better than it did with any other dose/grind setting, then you're done. If it tastes or measures under extracted or over extracted, you need to change the flow rate by adjusting grind and dose, or the shot time, or combinations thereof, to get back in the window. But with each iteration, you're shooting for the same brew ratio.

Once you find a flow rate that produces a balanced shot, you can fine tune the grind/dose to produce the optimum flavor while maintaining that flow rate. Even if you change grind and dose, when the flow rate is held constant, all you have to do is watch the scale and the time to know when the shot is done. It should be balanced because it was when you previously pulled at the same flow rate. You don't have to look for a color change.

Now, one thing to bear in mind is that the brew ratio mainly determines the strength of the espresso. After all is said and done, you might have a balanced shot with excellent flavor, but it's just too weak (Lungo) or too in-your-face (Ristretto). If that's the case you can change the brew ratio and dial in again.

Finally, the technique I use would not be appropriate for serving a line of customers in a high-volume cafe. It could be used by the head barista to dial in a particular coffee, and then the line baristas could either run the shot for the specified time or cut it at the color indicated by the head barista. I suppose when scales are eventually built into commercial espresso machines that might change things.

The bottom line is that pulling to a brew ratio is a technique that some (many?) of us find to be a more reliable way to consistently reproduce a given shot than trying to do that by watching for the blonding point. It is by no means a substitute for using taste as your guide for setting all of the shot parameters.

Hope this makes sense.
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Postby another_jim on Mon Sep 17, 2012 7:19 pm

While watching Heather Perry pull shots a few years back, and hearing her comments about blonding; it suddenly became very obvious that it is much better practice to let the shot to run too blonde than not blonde enough. Here is the reason:

It is self evident that if the shot hasn't blonded; it hasn't fully extracted. So unless you are going for a very edgy taste; it's a good idea to only end the shot only after it has gone quite blonde.

Final note: some baskets are more suited to longer shots, because they blonde slowly; while others blonde more quickly, and are more suited to shorter shots. If you like very high brew ratios; you may want to use whichever basket you have that blondes fastest.
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Postby mariobarba on Mon Sep 17, 2012 7:50 pm

another_jim wrote:
Final note: some baskets are more suited to longer shots, because they blonde slowly; while others blonde more quickly, and are more suited to shorter shots. If you like very high brew ratios; you may want to use whichever basket you have that blondes fastest.

Slightly Ot question
Just wondering Jim what property of the baskets dictate how fast a basket blondes. I mainly use a rancilio double basket which holds ~15-16g of coffee and whose holes seems quite large in diameter. Conversely, I also have a HQ double which holds a little more and has smaller holes in an octagonal pattern. I never really thought that the blonding point was perhaps due to the basket since grind and dose are always different for these baskets.
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Postby another_jim on Mon Sep 17, 2012 9:28 pm

I have no idea what the cause is. The old LM baskets blonded more slowly than any other. Going back to basics, this should mean that the coffee has less effective contact with the water in the old LM basket than in the others. But I can't understand how this could be the case; it makes no sense.
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Postby mitch236 on Tue Sep 18, 2012 7:49 am

I'll just throw this out there about my thoughts on blonding. I don't watch the color because if your technique is solid and your dose/grind are consistent, it is more reliable to use weights and time to dial in a shot. Color is too difficult a parameter to track accurately. Like Dick said, I use the VST refractometer to determine whether my shot is fully extracted, not some blonding point, which is different between even experienced baristas. Of course, taste is the final arbiter but I've found that my espresso tastes best when the extraction yield is within 18.5-20 on the refractometer.
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Postby TheSunInsideYou on Tue Sep 18, 2012 8:30 am

I also give preference to the weight and brew ratio of the shot, before I take in to consideration everything else. It's funny that this topic happened to surface right after I had a very confusing experience with a coffee's blonding point. I was using Mad Cap's Summer Solstice and was using a 19 in, 27 out (about 70% brew ratio), but I was also watching the blonding point, as i always do. For whatever reason, when my target weight was reached, the blonding appeared to still be holding out so--contrary to my typical weight-based extraction judgment--I allowed the shot to run a bit longer and figured I would tighten up the grind on the next one. But then when I tasted it, it was really obviously over-extracted to an almost undrinkable level. For whatever reason, the true blonding point, or the point at which the coffee is fully extracted, was quite a bit before the actual visual blonding point, which just goes to further confirm that you cannot trust it as a consistent sign that extraction is complete.

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Postby cpreston on Tue Sep 18, 2012 9:05 am

What goes around comes around-

Digital espresso or a way to consistency
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