I apologize if this information is covered somewhere else (I'm sure it is), but it didn't turn up in my searching. I was also hoping to get some more direct advice.

I'm trying to diagnose a flavor defect that I notice in my lattes. Sometimes when I'm drinking the foam part of my latte, I get this unusual bitter flavor. It's like tasting what pine wood chips smell like, or when you accidently eat a bit of shell with a walnut. Not an acrid or sharp bitter, just a woody bitter. I'm assuming this is coming mainly from the crema of my espresso, since it's only in brown foam.

Anyone have a good idea about what's causing this? I'm having a lot of channeling problems - is this just over extraction? Perhaps temperature? I noticed it appearing more in CC Toscano than in Katch's House Blend, for whatever that's worth.

Thanks!

It's a flavor coffee acquires if the roast is slow going to the first crack (from 300F to 395F bean temperature). It's not always a flaw, for instance, in lighter roasted Indonesian coffees, it's a necessary part of the taste. I don't know if this is a regular part of the Toscano profile or inadvertent.

The next observation is based on limited experience, but I taste more variability and slip ups in pro roasts in the winter than in other seasons. I think that roasting in winter, in poorly heated facilities, is a very tough job. Don't compensate enough for the cold, and you can get slow roasts and woody flavors; overcompensate, and the drums overheat and the roasts taste ashy.

It's impossible to identify defect from a latte.
Seriously.
It's even difficult with a straight espresso.

If you were cupping the coffee and were to get an unpleasant bitter, woody note (especially if it had the sort of pine-sap note you're describing) it would like to be a processing issue (I'd have guessed in that case that we were talking about an Indonesian coffee).
If it were a smokey woody note - or a flat woody note - those would be likely roast defects.

Perhaps my use of the term "defect" is a poor choice. I fully anticipated the cause of this flavor to be my fault - and still do. I've had a lot of Toscano espresso and lattes from Octane, which has solid baristas, and never experienced the same effect. (even recently)

But, I will say that the woody note is clearly apparent in some of my lattes. It's not in keeping with the "wonderfully sweet and mild" description.

However, today I managed to pull an almost perfect ristretto, and besides being delicious in a latte*, it had no bitterness of any sort. Maybe a much milder form of this flavor is balanced out somehow.

My question then is, what am I doing wrong the other times?



*I know, I should have stopped and drank it straight, but I was curious for comparison

Well, Fwiw, woody flavors can also mean too high of a temperature, or overextraction. Very well could be anything listed here, and I think it's fair to say, Jim and Chris have a bit more experience then I, when it comes to cupping and roasting, so, add a few grains of salt.

mini wrote:My question then is, what am I doing wrong the other times?

It would be helpful if you could provide information about how you're extracting the shot (dose, methodology, time, volume, temp); information on what changed; and what it tastes like as a straight shot.

I was hesitant to put this at first because I am not measuring these variables closely. Perhaps that's the answer to my original question, then.

I was hoping it would be an, "Oh, classic high temp problem. Just lower your temperature," type fix.

But if you are still willing to offer valuable advice, I'll put everything I do know, and then go pull a shot with more attention.

Usual routine:
Create a small hill in the basket and level off. Tamp with what I guess is about 30 lbs of force. Start the shot somewhere in the middle of the temperature deadband. Stop it when it goes mostly blond, at somewhere around 25-30 seconds. I try to keep it between the 1.5 and 2 ounces, but it varies with cutoff time.

The reason I do this is because I don't have a scale, for dosing or tamping purposes. Also, I've just had ton's of channeling problems - making timing each shot seem less valuable.

I would say 8/10 shots have at least one divet/hole where channeling is obvious. They start out ok and then 10 seconds in the whole stream turns blond. The puck has a perfect bolt pattern embedded into, so it's obvious that the puck has expanded completely against the dispersion screen. But when I use a curved finger to downdose, I seem to get just as many problems, and if anything more channeling holes, even thought there seems to be enough room.

Just now:
Gently leveled off and then took off a bit more with a curved finger. Usual tamp, which I believe is fairly consistent. The shot started out ok and then blonded at 15s. I stopped it at 21s because it was completely blond. It ended up being about 1.75 oz.

Tasted a bit weak, didn't have any spice warmth in the back of my tongue. The flavor balance seemed a bit odd, not rounded and creamy. I don't have enough of an espresso palate to comment much more. It didn't taste woody or particularly bitter, but I didn't like the immediate aftertaste.


Here is the puck from that shot. Channeling, boo!

This is what almost all my scooped doses look like. Like I said above, the flat leveled doses jam up against the shower screen and have somewhat similar channeling problems. Never at the edges, often in the middle.

Ask away if you want any more information. I really appreciate the help.

I suggest performing a traditional cupping of the coffee on its own to see if the flavor is in the coffee itself. A balsa wood flavor is from bringing the roast along too slowly, and it can be so distinct it is like chewing up a blasa toy glider! It is an unmistakable flavor, and not in a pleasant way.

I think it's worthwhile to try and break this into two distinct areas of feedback.

1 - "wood chip" flavour and potential defect (suggest cupping the coffee as noted above),
2 - espresso prep and methodology.

I don't think we're going to be able to get to the bottom of the former (#1) issue while also working on consistency/extraction issues (#2) so I think evaluating from taste of espresso is confusing / not worthwhile.

malachi wrote:I think evaluating from taste of espresso is confusing / not worthwhile.

I agree. I don't actually know now why I spent all that time yammering on about a poor extraction. You had originally said that careful flavor detection is near impossible with good, consistent espresso.

Therefore, I used the last bit of the bag in a cupping. I would like to note that the coffee is at the end of it's life (roasted 1/29), and that I have never actually cupped a coffee before. Also, espresso blends taste super weird to me when not brewed as espresso - this one in particular seemed very unbalanced.

I used about 7g of coffee with about 6 oz of water. The water was close to 200 degrees and I let it steep for 4 minutes. I tasted it using a tablespoon with the customary slurping technique but sampled it several times as it cooled.

Cupping Notes:
I couldn't decide at all what it reminded me of. It tasted faintly sweet, like brown sugar, but I couldn't pick out any other defining characteristics. It wasn't at all bitter, but it seemed dry, like a wine. As it cooled a little I started thinking that it tasted woody. However, I was getting some grinds in my mouth, which add an element of cellulose. At a medium temperature it had caramel, and maaaybe just a hint of chocolate, with a nice finish. When it was cooler it tasted weird, like sucking on bitter black tea leaves.

I think I was picking up some woody / bitter notes, but I wanted to taste those. The whole cupping seemed inconclusive to me. I didn't trust my impartiality. Therefore I decided to brew it again in an Aeropress, which is how I brew all my coffee that isn't espresso based. I'm more accustomed to this method, with better reference points.

___________________________________________________________________________________________

I used 1 1/2 Aeropress scoops with 2 1/2 markings of water. Slow saturation, 12 seconds of stirring, about 16 total seconds of brewing with 174 degree water. Then I topped off the 10oz mug with hot water. I just drank the mug as it cooled.

Aeropress Notes
Definitely a much rounder caramel at first, with a lot more sweetness. I noticed a quiet smoky flavor, slightly woody again. A little later it had a bad aftertaste of lime zest with a good after-aftertaste of sugar (this was a bizarre experience). Then came the bitter tea phase, but this time with a flavor pretty similar to my "wood chip" description. At a cooler temperature it distinctly tasted of dried/candied fruit (like oranges or bergamot). At a cold temperature it tasted like a heavily watered-down medium-quality scotch... not that I would know what scotch tastes like...

All in all I'm pretty convinced that there are some woody, bitter, woodchippy, balsa, whatever flavors in the blend. They come across similar to tea bitters, but with slightly different timbres than lean towards sap. They are not very strong, and I was hunting for them, but they were strong enough to not be imagined.

I'm not sure if this is a regular feature of this blend, but I would bet it is a slight flavor defect in this particular batch. It's not a big deal either way. I think I've been tasting this flavors in lattes with over extraction. I assume the above described flavors would be intensified with over extraction. As explained verbosely before, channeling is a common problem for me. I don't think it is brew temperature related, because I made a shot that was harsh in an entirely different way with a higher temperature.

That's my story and I'm sticking to it!

Any comments?