I am relatively new to home espresso, but, up until the last couple of days, I had been having pretty good luck. I will try to be as detailed in this post as possible.

My equipment:

Lelit PL041
Bartaza Preciso

Like I said, I had been pulling delicious shots using whole espresso beans purchased from Trader Joe's (nothing special, just the house brand of espresso beans). It took me a couple of days to get my grind and tamp dialed in, but once I did, the shots were quite tasty.

Well, I ran out of my TJs coffee and moved on to a bag of Black Cat. My first pull of the BC, while using the grind settings and tamp I was previously using, was way to quick. ~10 seconds to get 2oz. After a few tries I had my tamp and grind adjusted so I am getting 2oz in ~30 seconds using 20grams with the Black Cat. The problem is that the espresso is very sour. I don't know what to do. Here are some more details.

- Black Cat was roasted on 12/13 and sat under the Christmas tree until Christmas day (I got it as a present). I immediately double bagged it and put it in the freezer until I finished my Trader Joe's espresso. I took the Black Cat out on 1/11 and allowed it to defrost overnight.
- I have dialed in my grind and tamp and am getting 2oz in ~30 seconds using 20grams of beans
- I always allow my Lelit to warm up for at least 30 minutes. I leave the portafilter locked in the entire time.
- I do my best to prevent clumps in the portafilter and tamp evenly in order to avoid channeling
- I run ~3oz of water through the group head just prior to pulling the shot in order to further warm things up.
- The espresso looks great coming out of the portafilter. Color and speed of pull is great. I do not have a naked portafilter
- The crema looks great at first but significantly dissipates after ~1minute
- The final product is very sour. Almost like sucking on a lemon.

This exact process was working great and pulling delicious shots before I switched coffee.

From what I have read sour espresso is usually from under extraction or too low a brewing temperature. I have no way to test the temperature, but I don't see how that would be a problem being that I always give the machine at least 30 minutes to warm up. And I am also guessing under extraction is not the problem since I am getting 2oz in 30 seconds using 20 grams (but I could be wrong).

I am stumped and any and all help would be greatly appreciated.

Thanks everyone.

Jake

Flushing six ounces through the group just before the shot means that your brew boiler is now filled with cold water, which will cause your shot to be too cool. Try flushing a lot less - maybe an ounce or two, or waiting longer after you flush. On small boiler machines, you don't need to flush a lot, and in fact it's not a good idea unless your machine recovers temp very quickly.

Hope this helps.

Agree with Beezer on the large flush. It's not necessary on a single boiler machine, maybe just a couple of ounces. Are you allowing the machine to come back up to proper brew temp after the flush?

It also doesn't help matters that Black Cat likes a higher brew temp than some other blends. I find BC pulls best at 95C on my machine (La Spaziale Vivaldi II) while others work well for me in the 92C to 93C range.

I assume you already found another_jim's grind and dose sticky at the top of the tips and techniques forum. There's a lot of good advice there on how to adjust taste to your liking.

Thanks for the suggestions so far everyone. I need to update my post though. I should have said 2-3oz instead of 6oz of water. Don't know what I was thinking. Do you still think this could be the problem? Should I avoid flushing the group head altogether?

Thanks

Hi - I have had good results w/ BC. I took a class at Intelligentsia and their recommended parameters were:

18g dose, 27, out in 25-30 sec.

I found that using a finer grind and taking more time to get the same output generally helps w/ any sour notes

The reason you had such a big jump in the grind adjustment is because you coffee is a month old. Well past its prime. To compensate, you grind coarser and dose more for the save extraction time and volume. Sour espresso is often low temperature. As others have said you dont need to be flushing that much water but you will not get stellar shots from that coffee, it is just too old. Not to say you wont get something decent but it will be a far cry from a fresh bag.

5wallace wrote:
problem is that the espresso is very sour. I don't know what to do. Here are some more details.

- The final product is very sour. Almost like sucking on a lemon.

Jake

Roasting will also change a temper to bean tastes, not to mention about everything else mentioned above. A scoop or so for the roaster I take from a pot of 25lb hard beans off the local docks usually from high-grown, Central American countries, will yield varied results according to how I treat the roast processes, dial in the grinder, as well, accounting variance to a manual pull;- the only significant factor remaining unchanged, is slowing down appreciatively to allow the machine to reach its optimal or preset extraction temperature. S/O roasts and treatment for claims, besides, to distinctive flavoring are somewhat harder and demanding of equipment than deeper blends off the "Illy Manual" of espresso roasts. . .or, just maybe, that's entirely the other way around, bitter, tart or sour potentially being terms of distinction to cupping, least to mention lemon as a valid descriptor among purveyors of S/O. I would think to say that there's a world of difference now on the tabletop, in my gearworks' microcosm, for variance to extraction technique from the last S/O roast and this present one, which I allowed to develop more deeply into the second crack.

My advice? Go and read the children's fable called "The Emporer's New Clothes".

Then listen to what your taste-buds are telling you.

This pretty much explains why i'm having trouble with my BC. I recently tried their analog and still not quite right. I'm in Chicago and pretty much get the beans the day after roasting.

Any input on Metropolis Red Line, they are a hop, skip and a jump from your place.

Jim

another_jim wrote:I would hazard a guess that you are doing nothing wrong; but that you, as a beginner, have a far lower tolerance for lightly roasted, acidic espressos than you will have in a few years time. Black Cat is currently a light roasted blend with prominent orange flavors. I do not consider it suitable for beginners - it is fairly difficult to pull, requires top of the line commercial equipment, and even a great pull will taste very acidic, albeit with a lot more sweetness.

My only advice for Black Cat on your gear is to dose lower, grind a lot finer, and add sugar. Beyond that, you want to stick with "comfort food blends" that are lower in acidity and are heavier on the caramels and chocolates