A tale of sour espressos

Beginner and pro baristas share tips and tricks.

#1: Post by israguard »

Good morning everyone,

Hope the following is allowed & in the right section.

From day 1, I have always prepared milk based drinks on my LMLM & Kafetek grinder. I use a medium roast bean which I order on line from Sam James Coffee in Toronto (https://www.samjamescoffeebar.com/colle ... spresso-bk). I visited one of their Cafes and fell in love with the taste and since they were also using a LM machine.. I figured what the heck. Its been great for a few years and no issues thus far. Cappuccinos and latés are simply delicious.

I read a lot in this great forum about espresso tasting and what espresso shots "should taste like". So !!! At the office where I have a Breville Oracle touch I tasted the espresso yesterday.. Superb and smooth and this from a high end Lavazza bag. And this from someone who doesn't drink espresso ever.

I came home and made myself an espresso shot on my LMLM. Regretfully, I could smell the sourness from a mile away. Grind and extraction times are 100% within guidelines. But SOUR SOUR ... simply unbearable. However, pour in some beautifully frothed milk and you genuinely get a delicious cappuccino.

It was suggested to me that I need to adjust my temperature on the LMLM. My temp setting was on the absolute lowest. I used the dreaded wheel to increase and after one shot only, the sourness was gone. However, the shot tasted like krapp. Bitter and bland but sourness was thankfully gone. So this weekend I will have a lot of messing around to do in order to get a proper tasting shot.

I of course am grateful for any/all tips anyone here will have for me. No tip is too small..

Important lesson I have taken away thus far is that I really do wish the LMLM had a proper temp read out and not the wheel. I wont upgrade to a new board to use the app.

And for anyone like me who does only make milk based drinks. Start with a great shot first. Its incredible how the milk masks the lousy shots.

Thanks for listening

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#2: Post by lessthanjoey »

Others with a little more time than I have right now will chime in thoughts here with more clear advice on the straight shots, however if your goal is to make a good milk drink, to a large degree it's irrelevant how it tastes as a straight shot. Milk interacts with the flavors of espresso in interesting ways - muting some flavors, allowing others through, and changing the perceived balance. While making espresso shots that you like is a good goal, they may not come from the same beans for you, and they may make a worse milk drink.

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israguard (original poster)

#3: Post by israguard (original poster) »

Thanks for the quick reply.

This is why I am happy I have a second professional grinder @ home ( https://www.cunill.com/cafe/downloads20 ... IC-500.pdf ) which I will load up with the Lavazza beans.

I honestly never did realize until reading your comments the "effect" milk has on a shot.

But once in a while I would like to enjoy a nice Esspresso shot on its on. And if the base of the drink (a beautiful Esspresso shot) was superb on its own.. it can only elevate the milk based drink.. At least I hope it can.

Prior to reading your comments. I truthfully was beyond discouraged.

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#4: Post by lessthanjoey » replying to israguard »

Happy that that helped! One way to think of it simply (although in reality it is more complex, and not a simple dilution) is this: if your espresso tastes perfectly balanced, then as you dilute it with milk that balance will shift. If it starts off too strong in some way, the milk might dilute it in a way that brings it into balance. Of course you can also get fantastic espresso shots that turn into fantastic milk drinks, but a lot of that depends on how much milk, and what the characteristics of the beans are, as well as your individual taste! So, it's not really a fundamental goal :)

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#5: Post by Ken5 »

If all else is good it could be the beans. What beans are you using? Perhaps someone here has experience with them.

israguard (original poster)

#6: Post by israguard (original poster) »

Make and model of my beans are in my initial post... i put the URL.

This is a truly magnificient bean.. Hard to explain how smooth it is. Roasted Feb 15 2021

israguard (original poster)

#7: Post by israguard (original poster) »

I will memorize this as I spend my weekend grinding and cussing as I search for the perfect shot.

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#8: Post by Peppersass »

The beans should be allowed to rest for at least 3-5 days after roasting, possibly longer. This is particularly important for roasts that range from light to medium. As your medium roast beans were roasted on 2/15, I'd recommend trying them again on the 20th. Darker roasts usually require less resting time, but 3 days is still a good rule of thumb.

The reason for resting the beans is that CO2 builds up in them during the roasting process. It can take several days to two weeks for the beans to fully "outgas". This is why coffee bags have one-way valves. The CO2 can escape without oxygen getting in (oxidation causes the beans to go stale.) When you brew beans too soon after roasting, the CO2 comes out and interferes with extraction. You may have seen this with drip or pourover coffee -- a huge plume erupts as hot water hits the coffee.

Under-extracted coffee tastes sour, which is what you experienced. Light and medium roasts are more susceptible to under-extraction than dark roasts.

Now, if the beans you had at work were the same, then it may be that differences in the grind setting, dose and/or temperature between home and office may be partly responsible for the under-extraction at home. But it's best to eliminate the CO2 issue before playing around with those parameters.

Note that there could be other differences, such as the pre-infusion time between the Breville and LMLM machines. The LMLM has an 0.8mm flow restrictor, which sets the ramp time to full pressure. The Breville might have a different size flow restrictor. Differences in pre-infusion flow rate can influence the extraction yield. Rather than playing around with that rather complicated parameter, you might want to try a finer grind at home and/or increasing the shot time, which should extract more from the coffee.

Finally, while I agree that milk changes the taste, and can cover up less-than-ideal shots, I'm not in agreement with the premise that milk changes the coffee so much that a milk shot might taste better than a well-prepared straight espresso shot from the same bean. In my experience, the better the straight espresso shot, the better the milk drink.

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#9: Post by Ken5 »

israguard wrote:Make and model of my beans are in my initial post... i put the URL.
Oops... missed that :(

israguard (original poster)

#10: Post by israguard (original poster) »

Thanks for taking the time.

Beans @ office on Breville are Lavazza.

I will buy same and bring home to try this weekend on the LMLM. I agree with you that ideally the espresso shot should be perfect before adding milk. A lot of exciting experimentation coming up.