I have been doing some reading about bitterness, acidity, and sweetness when roasting for Espresso.

Therefore, to maximize sweetness you want to minimize the carmelization of sucrose, yet you do not want to roast too lightly or bitter tasting compounds will not thermally degrade

from http://www.coffeeresearch.org/espresso/roasting.htm

I was reflecting the other day; I used to drink more straight espresso, but for the last year or so, I have been making cappuccinos. This timing was eerily coincident with my purchase of a Hottop which caused me to have to re-learn the settings and nuances of a new roaster. The result: mostly bitter espresso with lots of body that would leave "tire tracks" on your tongue if you drank it straight, that worked very well in cappuccinos. So I set a goal to expand the envelope a bit and search for more sweetness.

The coffeeresearch site states that when roasting for espresso you want to maximize sweetness by minimizing the carmelization of sucrose...hence - roast lighter!!??!

So I grabbed some SO Ethiopian Sidamo, roasted it about 1 min 45 sec past 1st crack, dumped and cooled. I felt like something was missing; I did not get the billowing smoke of 2nd crack, nor snapping sound of the 2nd crack, and the beans were lighter with no visible oil. I ran my first shot at high temp

B A M! Blueberry pop-tart filling, carmel, sweetness, smoothness, the slightest tint of a lemony acidity but no sourness. Has American coffee culture led us all to believe that espresso should be roasted dark and oily? Sure dark roasts cut the acidity, but bitterness overcomes sweetness as you go darker.

So, to all the home roasters out there: What do your friends say when tasting your home roasted espresso?

This is really smooth
This is as good as a coffee house
This is not as bitter as my favorite coffee house
This is so SWEET!

How many times have your customers or guests said: "This espresso is really sweet!"

Lets see if we can get our friends to notice the sweetness of our espresso. What are your roasting tips for maximum sweetness?

Sugars disappear in two ways, Maillard reactions from 300F to the first crack, and caramelization afterwards. So for maximum sweetness, roast fast up to the first crack, then keep it light, but slow it down, so that most of the acids and grassy tastes have time to roast out.

However, many coffees have very fine maillard and caramel flavors, for instance the honey and almonds of a good Bourbon, the molasses and clove of an SL28, or the chocolate of Ethiopian and Yemen coffees. The more sugar in the bean, the more you can use up to get these tasty flavors while still keeping the overall balance sweet. That is why the sweeter the coffee, the greater the roasting options, and (mostly) the more expensive the green.

I appreciate this perspective, Jim, and the timeliness of your writing [my reading] it. I have some 10 day rested Sidamo roasted City++ with noticeable chaff in the grounds. Brewed, it has loads of black tea with blueberry background. I hadn't pulled an espresso from it until this morning (been leaning toward my vienna Mexican Oxaca). I pulled 2 doubles and there was a sweet chocolate that I'd never tasted in the brewed cup. I didn't get the blueberry I'd hoped, but what I did get was great.

Yes, a light roast can and will pull espressos in my kitchen.

CHAD

Jim, once again you have helped me improve my espresso. This whitepaper gave me a better understanding of over/under extraction.

http://www.coffeecuppers.com/Espresso.htm

Highlight #1: The acidity we all struggle against in our espresso comes more from the shot being unbalanced, than from the acidity being too strong.

Highlight #2: In Italy 13g is the dose for double espressos yields a 20% to 24% solubles extraction. Elsewhere, where espresso is specialty coffee, higher doses yield 16% to 20%. So dosing by filling the portafilter and leveling to the basket's rim gives us a higher dose than the Italian norm, and causes under-extraction.

Highlight #3: Higher yield shots tended to a more bitter balance, and lower yield to a more acidic balance. This is because the acidic compounds extract faster than the bitter and caramel compounds.

My experiment: I have been dosing and leveling using the basket rim - similarly to nearly EVERY video and explanation I have seen. This yields me an 18g dose using the LM double basket. My shot: a bit bitter and a bit sour, but similar to what I have been used to. So I measured 13g and after some grinder tweaking... BAM!

Acidity: more crisp and lively at 13g. The change is amazing, the acidity is still there, but it is crisp and drinkable. At 18g, the acidity was overwhelmingly sour.

Sweetness: I didn't notice an increase in sweetness at first taste, but the finish was sweeter and had more caramel.

Bitterness: About the same, except the bitterness tasted more like the chewed bean than bitter compounds.

So - if you are a home roaster like me, and struggling to reduce acidity and get more sweetness in your espresso, read Jim's whitepaper and check your extraction. You might actually be under-extracting and leaving sweetness and caramel tasting compounds in the puck! I cannot wait to wake up to my morning espresso tomorrow!

Don

The odd thing about that paper is that the taste changes by dosing work for most people; but the extraction results don't replicate. That leaves the advice on how to work the dose correct, but all the fancy reasoning I gave incorrect, and me scratching my head wondering what I missed.

I am wondering if it has something to do with the total surface area of the grounds. When I decreased the dose to 13g, I definitely had to grind finer to keep the shot timing > 20s. So maybe we are getting more water to coffee contact with lower doses ground finer?

What is really interesting to me...the 13g dose produces the same shot appearance and volume as the 18g dose. So at 18g there must be more "unspent" coffee, or "partially spent" coffee which ties to your yield argument.

vanboom wrote:So at 18g there must be more "unspent" coffee, or "partially spent" coffee which ties to your yield argument.

You certainly get a drier puck at 18+ grams.

another_jim wrote:The odd thing about that paper is that the taste changes by dosing work for most people; but the extraction results don't replicate.

Did you get measurements of the TDS for a 13g extraction vs. an 18g? How do they compare?

vanboom wrote:In Italy 13g is the dose for double espressos yields a 20% to 24% solubles extraction. Elsewhere, where espresso is specialty coffee, higher doses yield 16% to 20%.

What were the degrees of roast for the two espressos used for this comparison? I'm under the impression that Italian roasters, generally speaking, take espresso much darker than most specialty roasters in the US (Think "Full City" vs. "Italian" roast). Because darker roasted coffee extracts more quickly, perhaps this is a confound in the comparison. I'm sure you thought of this, Jim. I read through the data set at the end of your article (which was excellent, by the way) but I didn't see anything that addressed this specifically. Maybe I just missed it, though.

btw: I am roasting to the first snap of 2nd crack.

The paper makes two points

-- you can work the taste by changing dose. This has become SOP.

-- lower doses need to be ground finer, and therefore extract more. This was true for the Lux, Mazzer Mini and Versalab M3, but not so much for the Titan grinders, which had high extraction rates at all doses. In fairness, the high dose shots from the Titans taste better than from the smaller burr grinders, while the smaller grinders are competitive at lower doses. But changing dose still changes the taste on the big boys, only in a more acceptable range.

... in 'spro heaven... dosing lighter changed my life

My objective taste tester is a Seattle friend. Yesterday he said: "this is as good as I can imagine espresso"

Thanks again Jim!