Scenting Roasted Coffee

Abstract

In this experiment, samples of roasted coffee were scented with different spices, brewed, iced, and assessed for aroma.

Introduction

There is contention among industry professionals as to how much aroma is absorbed by coffee after it is roasted. Additionally at the 2018 America's best cold brew competition in Baltimore, one of the best performing competitors used a coffee scenting procedure that created an iced coffee with potent floral and herbal aromas.

Hypothesis

Given that we were using a scenting procedure similar to what we understood the procedure to be of a company that scored well at America’s best cold brew, and using a high ratio of scenting material to coffee, our hypothesis was that our iced coffees would have a strong flavor contributed by the scenting material.

Methods

1. 100 grams samples of roasted coffee blend well past its degassing (over 7 days old) were sealed in airtight 8oz bags with a one-way valve.

2. In sample A. 2 3” cinnamon sticks were added

3. In sample B 7 grams of loose peppermint in a loose tea T-sac was added

4. In sample C 7 grams of whole lavender flower in a loose tea T-sac was added

5. Samples were held sealed at room temperature for 7 days.

6. Samples were then brewed hot at 50g / Liter water for 3 minutes then poured over ice

7. Samples were then blindly tasted and notes taken

Results and Discussion

The 2 tasters did not perceive any added flavors in the iced coffee and could not reliably even assess which coffee was scented with which material. Perhaps coffee can only be scented while it is degassing. Perhaps 7 days is not long enough to scent. However if significantly more than 7 days are need to scent a coffee than coffee freshness issues will impact the final cup.

Conclusion

Our research provided strong evidence disproving our hypothesis. We conclude that scenting coffee post degassing provides negligible flavor. An experiment using coffee still degassing, longer scenting times, and higher scenting material masses would be interesting to see.

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Abstract

 In this experiment, various samples of green coffee that had lost moisture content were rehydrated. These coffees were then roasted both with reduced moisture content, and rehydrated, and then cupped side by side. This was done to determine if improved cupping scores would be attained by rehydrating coffee that has lost moisture content.

 Introduction

 One of the most common, complex and arduous ordeals with maintaining specialty grade coffee is maintaining it's desired moisture content from the point of harvest and processing, all the way through the multiple climates, environments and months it usually takes to get to the roaster. Coffee is most often transferred via ocean freight, spending weeks and even months at sea. From here it spends time on railroads and in warehouses. All of these destinations have varying climate conditions that can alter the moisture content of coffee significantly. Hermetically sealed bags have aided this problem tremendously. However, not all farmers can afford to go to such lengths to bag their coffees in such ways. And even if they can it's no guarantee moisture level may not be affected at some point.

 Hypothesis

 We couldn't really find any research anywhere else on this subject matter. There's plenty of research on how moisture content can be lost or can be maintained. But what if you took green coffee that has gone down in moisture content and brought it's moisture back up? When moisture content is lost from green coffee, the very essence of what makes specialty coffee special goes with it. The subtle nuances and potency of aromatics are taken with the water as it evaporates. So, what if you brought the moisture level back up? Would these aromatics be better restored? Would what is left in the green coffee be better reserved? Our hypothesis was that be renewing moisture content to green coffee that was below ideal would improve cup scores.

 Methods

1. The sweet spot for desired moisture content in green coffee is between 9-12%, with 11-12% being what is typically considered ideal.

2. We took samples of three different types of coffees we have in stock: one we roast light (a Yirgacheffe), one we roast medium(Nicaragua Jinotega, Finca Las Mercedes), and one we roast dark (Sumatra Aceh).

3. At this point each had a moisture content of 11%. These samples were left to sit out exposed to the air until their moisture content was at 10%.

4. Next we placed each sample in a separate air tight sterile container. Sterile cotton was saturated with filtered water and placed inside of the containers with the green coffee samples. The water-soaked cotton did not touch the green coffee, it was sealed in the container but at a distance so that water could be absorbed through the air, not direct contact.

5. In a few days moisture levels of the green coffee were up to 12%. We then roasted each of the samples along with a batch of each coffee type from it's original bag in it's original state and moisture content of 11%.

6. Blind cuppings of each coffee were done in sequence: light roast original vs light roast rehydrated, medium roast original vs medium roast rehydrated, and dark roast original vs dark roast rehydrated.

 Results and Discussion

The results were more varied than you may imagine. In some cases, the rehydrated coffee scored higher. But in more cases the coffee as it was in its original state scored higher. And in all, the variances in score were not that drastic when comparing original sample vs rehydrated sample roasted in the same manner.

Conclusion

Our research provided strong evidence disproving our hypothesis. We conclude the rehydration of green coffee does not have a profound affect on cup quality either way. Since there was no clear evidence of a vast improvement with rehydration, we see the amount of work and effort that would go into rehydration versus the results don't add up to making it worthwhile. But that isn't to say more people doing more experiments such as this should be discouraged, quite the contrary! More research on this topic is necessary and we urge roasters to do more experiments like this themselves and to share the results as well.

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Muggswigz Coffee & Tea co. Research at www.muggswigz.com Feb 05 2016

© 2016 Muggswigz Ltd.

Creating a Molded Coffee

Abstract

In this experiment, various samples of green coffee were intentionally allowed to mold. Different mold and different times were tried and the resulting coffee roasted the sampled.

Introduction

The flavor of mold in coffee has been a taint but the flavor is popular and well-liked in some cheeses. We sought to discover if a controlled molding process could be performed on green coffee beans to create a pleasant and interesting cup flavor profile.

Hypothesis

We couldn't find any research anywhere else on creating a controlled mold to create a flavor attribute in coffee. Our hypothesis was that creating a controlled molded green coffee be using one of the methods we tried would result in a pleasant and interesting cup profile.

Methods

1. Sample set (1) were 250 grams of the same unroasted central American washed coffee roasted on our sample roaster using the profile we use for that coffee as a control.

2. Their were 6 samples in Set (1). Various amounts for filtered water was added to each sample and placed in an air-tight container. The water amount for the 6 samples were 5mL, 10mL 20mL, 30ml, and 40mL

3. Sample set (2) contained 3 samples of 125 grams of the same unroasted central American washed coffee with 25mL filtered water in an air-tight container. One sample was inoculated with 1mL Roquefort cheese mold, one sample was inoculated with 1mL Maytag blue cheese mold, and one sample was left un-innoculated.

4. Sample set (3) contained 3 samples of 125 grams of the same unroasted central American washed coffee with 35mL filtered water in an air-tight container. One sample was inoculated with 10mL Roquefort cheese mold, one sample was inoculated with 10mL Maytag blue cheese mold, and one sample was left un-innoculated.

Results and Discussion

Sample set (1)

Sample set (2)

Sample set (3)

Conclusion

 Our research provides strong evidence disproving our hypothesis. The coffees were cupping by both a cupper that enjoys blue cheeses and a cupper that does not. But cuppers scores for all the samples were very low. It seemed the flavors of the coffees themselves were very weak, leaving behind a cardboard like backdrop for a mostly unpleasant cooked-mold flavor. As are samples were limited and time period for the molding very short, more research on this topic is necessary and we urge roasters to do more experiments like this themselves and to share the results as well.

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  Last time I wrote about some of the basics involved with brewing espresso. Today I'll write a little about how roast degree affects the espresso. The darker the roast used for espresso, the more acidity, sweetness, and the coffee's natural flavor profile decreases and bitterness increases. So why would one use a very dark roast for espresso (also called a southern Italian roast)? Well, for one, the bitterness and carbony taste that often comes with a southern Italian roast cuts through milk better than a central Italian or northern Italian roast because it has more of a dark bitter punch than the other two (southern Italian roast contains more carbonized sugars while lighter roasts contain more caramelized sugars).

   Using a darker roast for espresso also makes brewing a consistent shot much easier. Using a lighter roast provides one with the potential to brew a very rich, sweet, shot with lovely caramel flavor, and full of the coffee's natural flavors. However, the sugar structure of a lighter roast is easily damaged during brewing. This type of espresso can be ruined so many ways in brewing in handling that I won't get into it here. Blending beans for a northern Italian roast presents a challenge because the coffees one uses are more important than when blending for darker roasts because more of the actual coffee flavor and characteristics will come through in the northern and central Italian espressos. The largest concern when blending for a northern Italian espresso is that the blend should be low-acid when roasted to the proper degree. A Mocha / Java is widely considered to be the best blend for this roast, or, partially because Mocha and Java beans are quite pricy, a similar, less expensive blend of Ethiopian Harrar and Sumatra is often used. The balance of bitterness and the sweetness and varietal flavors lies further toward the bitter end in a central Italian roast than the Northern roast, but the coffee's varietal distinctions are still apparent.

   For those who don't remember, I started this subject a couple issues ago because people mentioned that are espresso tasted different then what they have had previously. One of the primary reasons is because we use a central  Italian roast while most espresso places will use a southern Italian or even darker roast. About a month ago, I talked to a roaster from Cleveland about why the large coffee chains use such a dark roast. I told him my theory; which was that 1) Because the USA drinks espresso-based beverages with much more milk on average than Europe, the large chains are ensuing that some bitter taste cuts through all that milk. and 2) Because of the quantity of labor the large chains need, it would be every difficult to train baristas to competently and efficiently handle the lighter roasts.

   He politely told me that my theory was wrong and told me his. He believed that because of the huge quantity of beans needed by the chain, they are unable to be selective about the blends and bean quality of the coffee they need roasted, and therefore to achieve any satisfactory and consistent espresso, they need to roast to a southern Italian roast and even darker. He had a good point. But I'm a pretty stubborn person, so I'm going to say that there is probably truth two both of our arguments, and their decision to roast so dark was probably based on a combination of those reasons.