So I work at Dunn Bros. Coffee in MPLS, MN.

I'm hoping you can help me troubleshoot our espresso or give me ideas that might help to make it taste better.

we use a blend of roughly 80% Colombia 20% Sumatra
I've heard that our coffee ranges in the upper 80's in terms of score.

We roast all of our coffee in house in an older San Franciscan
we usually use our espresso 2-3 days after roast.
the roast is relatively light. brought just into second crack, until the first sign of oil is encountered. then it's dropped. Dunn Bros. calls this a Vienna Roast.

Dunn Bros. Coffee espresso standards that I usually am required to follow:
we have La Cimbali Machines
double baskets in portafiliters that don't have downspouts but aren't bottomless. just one spout.
16g pulled to 2 ounces ranging between 18-23 seconds.

the espresso, in my opinion is very light (color) lots of crema (up to 1.5 ounces in a 2 once shot.)

in terms of flavor, it varies pretty regularly.

it's usually very acidic. almost astringent. it's difficult to drink two ounces of it. I had espresso at the SCAA show last year, from intelligentsia, Alterra and a few others. they were all very pleasant and very balanced and easily cuppable.

I'm wondering what I can alter behind the bar that will make me able to drink our espresso.

thanks for your help!

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Hard to comment without cupping the blend myself... but I am assuming the blend is fairly well accepted by customers at present, and was developed over time by Dunn's roastmasters (meaning...maybe the issues you are finding are not necessarily blend related). I recently was at an expo which required I use a +4U machine...hi tech. Now I am used to drinking my espresso through the traditional machines I normally deal with. Using the +4U initially the espresso was terrible. As I roasted myself I knew it for sure was not the blend or the roasting... fortunately the tech guys were also at the show so they gave me a crash course on using the +4U and within a few hours I was pulling nice, sweet, fat shots. So... in my case it was machine related. Not wanting to step on your roastmasters toes, I would perhaps roast slightly darker... or roast the Colombian and Sumatra seperate (Sumatra for sure a bit darker) and then blend post roast. Sumatra on a lighter roast tends to lack body If its a Lintong especially it will add a great deal of percieved sharpness to an espresso blend. (IMHO). I would also let the blend rest to around 5 days. I am no expert on Colombian, but for sure the Sumatran Origins NEED 5 days to rest before drinking.
I would try two a two spout portafilter pulling 1.5 ounces (ristretto) for 30 seconds. Just a suggestion but a light roast really shouldn't be that bitter!
Hey Keith,
I was in Milwaukee a few weeks ago and got an espresso from Dunn Bros. My double shot was 4+ oz, very strange. Like you said, very acidic and VERY hard to drink.

I don't know how the franchise agreements are set up, but if possible you may try to mess with the blend a little. Maybe a little less on the Colombian and a little more heavy on the Sumatra.. Echoing what Alun said, definitely want to blend post roast. The sumatra really shines at a darker roast while the colombian is better a little lighter. Pre-roast blending does a disservice to both coffees by not allowing each flavor profile to be at its full potential (IMHO).

We also have an espresso offering that is a col/sum blend. And it starts to come around on day 5-6.

Alun Evans said:
Not wanting to step on your roastmasters toes, I would perhaps roast slightly darker... or roast the Colombian and Sumatra seperate (Sumatra for sure a bit darker) and then blend post roast. Sumatra on a lighter roast tends to lack body If its a Lintong especially it will add a great deal of percieved sharpness to an espresso blend. (IMHO). I would also let the blend rest to around 5 days. I am no expert on Colombian, but for sure the Sumatran Origins NEED 5 days to rest before drinking.
Others have already touched on the things that stuck out to me.

try holding a bag of beans over until its 7days post-roast - compare it to the 2 day stuff.

I'm with Brendan on extraction, as he suggests, try adjusting your grind to where you're getting 1.5oz in 30sec. Try it everywhere in between too, take notes, it'll look better when you present it to "The Man" for a change in SOP.

Poorly calibrated machines are all too common of a problem in the chain environment, imo. If everything else were sorted, personally, I'd want to play with the machine. The boss might not be down with that though - so get some closing shifts... ;-)
IMO: age your roast, up your dose, grind for 25-30 sec. shot

Unless you have specifically been given control over the roast parameters, I wouldn't mess with it - much safer to "experiment" with 18 grams of coffee than 10 lbs.
One thing I am not reading in this is if this coffee had a different flavor profile and it changed all of a sudden...All others have given you some really valuable advice and I would like to add just a little more I agree with all the checks and cross checks but my suggestion oif the day would be this...make sure the water filter has been changed recently and the equipment is properly cleaned and maintained and calibrated.
Agreeing here as well on many of these suggestions. 2-3 days post roast seems really young, and is probably the root of your problem... lots of things you said made me think this. I bet the bubbles are pretty coarse in the crema as well? 5-7 days seems to be what most here shoot for. Our espresso is undrinkable on day 2, buttery and beautiful on day 5.

Also agree with the idea of pushing the upper end of the extraction time window. 18 seconds seems fast for 2 oz/16 gram. This dose sounds fine to me though.

Good luck. Try this stuff and post back.
I am agreeing with many of the replys I have read. Also some have suggested that there is not enough information given for anyone to be spot on with our advice, I agree. However after you filter through our replys and use some of the suggestions, you should be closer to better extraction, and better taste.

Keith you said that you are getting an acidic taste with astingency, yet the single origins that you are using are not very high in acidity. So, if the beans look light brown, and the crema is light in color with a thin body, it appears that your beans are under roasted, which hold more acidity than normal. Also, it can be that your blend has not oxygenated long enough to degas and marry the blend. (This is just one of several possibilities) I would try a darker roast.

Start from the beginning and review your extraction variables:
1) A clean, good functioning grinder-Ability to grind to a fine grind without mashing or heating the coffee. If you cannot get good grind consistancy, you may need new grinder burrs. Too fine a grind will produce bitter and or astringent coffee.

2) Good clean water slightly hard.

3) The water temperature needs to agree with the degree of roast. Generally, Dark roasts do well about 190o to 200oF. Lighter roasts do well at higher temperatures 205o F or slightly higher. There are exceptions.

4) Proper water pressure is necessary for a good extraction. Sometimes older espresso machines drop in pressure over the years so keep an eye on it.

5) Proper coffee dosage to the amount of hot water dosage. I am sceptical about the portafilter method that you are using. A double spout portafilter with a basket that will hold close to 16 grams should give you an even extraction and
a better pour. Pack firm to level the coffee dose and provide an even extraction. Adjust your water dose to one and one quater ounce per shot glass, or two ounces of water total. This will provide two single ristrettos in the amount of 3/4 of an ounce of liquid espresso, or a total double shot of one and one half ounce of thick espresso in the cup.

6) Pour your espresso in preheated containers when pulling the shots. If you allow the shots to sit for more than a few seconds, too much of the sweetness evaporates from the shots, and bitterness over rides the taste.

7) Then there is always barista error >:-)~

This is a good group of educated coffee people in this forum. Make mine a double ristretto-macchiato to GULP!
Why don't ya cover it up w/ a little latte art?

Of course I meant astringency, although astingency sounds like an interesting word related somehow to stingy :-)
First off, thanks to everyone for your advice and help.

Unfortunately, I'm unable to mess with the blend of the espresso as it's delivered as a blend and then roasted in our shop that way.
I've talked to the roasters at my shop, and were able to tweak things in the roast.
darkness, aggressiveness and roast date.
I'm going to save a bag for a few days and see how it holds up at 4-7 days and then maybe even later at a 7-10 day.

I also am not able to mess with the quantities of espresso poured.
our drinks are set up to use the shots we have
a 2oz. and a 3oz.
both pulled in the same double basket portafilters with 16g

our equipment is pretty well maintained,
our service rep comes in at least once a month, to check burrs and the filtration system.
we purocaff at the end of the day, and then usually run three shots through each group in the morning to season and adjust the grind for the day.

we use an Azkoyen Capriccio grinder that automatically weighs out the dosage.
then we hand tamp with the automatic lever tamper.

when I dose, I wipe off excess grinds on the rim of the basket, one light tap on the counter then tamp, and wipe again.
purge group head.
insert into the group head and pour immediately so that no "cooking" occurs.

our machine apparently does not have a preinfusion setup, so the first signs come out pretty quick, 1+ second.
measured from the press of the button the 2 ounce shot should be between 18-23 seconds, though I like to draw it closer to that 23, if not a bit over.

the espresso is very gassy, which becomes a big problem in terms of presentation and apparently in flavor, so I'm going to see what we can do about pushing the roast date back a bit further.

thanks Rich,
I heard through our service rep that our machine was set up with jets that keep the temp down to 194? I don't know why this would have been done but apparently that's what Dunn Bros. does.
our espresso machine is less than a year old, so I don't think that pressure is an issue though I've noticed that when using two or three group heads at the same time the pressure drops down to less than 7 bar?
I don't know if that is just our machine being inconsistent or if most machines will drop that much.

haha, thanks Shawn.
if the espresso wasn't so gassy I wouldn't have to deal with that.
maybe help me out eh?

thanks again for all of your help guys,
I'm going to age the espresso and give her another go.
I'll keep a log to see what I notice.

another problem that I may encounter which may be up for a different discussion is that I am in MPLS, it's December and our coffees are kept in a warehouse that is not humidity controlled so I've heard this can have a devastating effect on the flavor of our coffees.
Alun, what is the benefit of letting the coffee rest for several days after roasting? What happens in those 5 days?
What differences would I find between drinking it the same day and drinking it after 5 days?

Do you let it rest in an air-tight container or in a paper bag, or what? Thanks.

Alun Evans said:
I would also let the blend rest to around 5 days. I am no expert on Colombian, but for sure the Sumatran Origins NEED 5 days to rest before drinking.

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