exBEERiment | Brewing With Coffee: Cold Brew vs. Whole Bean Added At Packaging In An American Stout

Author: Steve Thanos

While brewing grains come from various types of grasses, namely barley, and coffee beans come from the seeds of a specific fruit tree, both can be roasted to produce similar characteristics. As such, many modern brewers use coffee as an adjunct, often pairing it with darker styles like Porter and Stout to impart a unique depth of flavor that cannot be accomplished with barley alone.

A decision brewers have to make when using coffee is how to add it to the beer, with one of the simplest approaches involving tossing a measured amount of whole beans into the keg at packaging. However, a number of other methods have been developed over the years that are believed to impart more desirable characteristics, a popular one being to use cold brew coffee in place of whole beans.

I’ve made a handful of coffee beers over the years and have always relied on using cold brew, the results of which I’ve generally been pleased with. Even so, while designing a batch of coffee Stout recently, I began to wonder how effective the easier method of adding whole beans might be and designed an xBmt to test it out!

| PURPOSE |

To evaluate the differences between an American Stout where cold brew coffee was added at packaging and one where whole beans were added at packaging.

| METHODS |

For this xBmt, I went with an American Stout recipe I’ve used in the past as a base for coffee beers.

Coffee & Contemplation

After collecting 2 sets of water and lighting the flame to get them heating up, I weighed out and milled the grains.

Once the water for each batch was adequately heated, I incorporated the grains then checked to make sure both were at the same target mash temperature.

While the mashes were resting, I prepared the kettle hop additions.

Once each 60 minute mash was complete, I sparged to collect the same pre-boil volume then boiled the worts for 60 minutes before running them through a plate chiller.

Refractometer readings showed both worts achieved the same target OG

The filled carboys were placed in my chamber and left to finish chilling to my desired fermentation temperature of 66°F/19°C for a few hours before I pitched a pouch of Imperial Yeast A10 Darkness into each.

With signs of fermentation activity absent after 3 weeks, I took hydrometer measurements showing the beers had reached the target FG.

At this point, it was time to introduce the coffee to the beers. After sanitizing and purging two kegs, I gently added cold brew coffee that I made by steeping 0.5 lbs/227 g of course ground beans in 0.4 gal/1.5 L of cool water for 48 hours to one keg, while the other keg received the same amount of whole beans encased in a muslin bag.

I then pressure transferred the beers into the kegs and placed in my keezer where they were left to condition for a week before they were ready to serve.

| RESULTS |

Huge thanks to the crew at Werk Force Brewing for allowing me to collect data at their rad brewery. A total of 21 people of varying levels of experience participated in this xBmt. Each participant was served 1 sample of the beer made with cold brew coffee and 2 samples of the beer made with whole beans in different colored opaque cups then asked to identify the unique sample. While 12 tasters (p<0.05) would have had to accurately identify the unique sample in order to reach statistical significance, 13 did (p=0.007), indicating participants in this xBmt were able to reliably distinguish an American Stout dosed with cold brew coffee at packaging from one made with whole beans instead.

The 13 participants who made the accurate selection on the triangle test were instructed to complete a brief preference survey comparing only the beers that were different. A total of 8 tasters reported preferring the beer made with cold brew coffee, 3 said they liked the beer made with whole beans, and 2 had no preference despite noticing a difference.

My Impressions: Out of the 5 semi-blind triangle tests I attempted, I correctly identified the odd-beer-out 4 times. I perceived the beer made with cold brew coffee as having a well-rounded coffee flavor whereas one made with whole beans had a stronger roast character that seemed to fade quickly after swallowing. While both beers were enjoyable, I had a slight preference for the cold brew batch.

| DISCUSSION |

Coffee and beer go hand-in-hand, as is evidenced by the fact so many breweries offer coffee beers, many of which are darker styles like Porter and Stout. When making such beers, brewers have a few different methods to choose from, a common one of late involving the addition of cold brew coffee at packaging, though many report positive results by using whole beans. Tasters in this xBmt were able to reliably distinguish an American Stout dosed with cold brew coffee at packaging from one made with whole beans instead, which supports the notion that each approach contributes unique characteristics.

It’s possible these results can be explained by the additional water added to the batch made with cold brew coffee, though seeing as I relied on a standard method for making the cold brew, this can be viewed as a function of the variable. Interestingly, while I perceived the batch made with whole beans as being slightly more roasty, the overall coffee character was similar in both beers, and a majority of tasters reported preferring the one made with cold brew coffee.

Having always used cold brew coffee when making coffee beers, I admittedly had some bias when going into this xBmt, though I did my best to suspend this for my own semi-blind trials. In addition to consistently being able to tell the beers apart, I preferred the one made with cold brew, which I viewed as personally validating. While I thought the Stout made with whole beans was perfectly fine, making a batch of cold brew coffee requires so little additional work that I’ll continue using this method in the future.

If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below!

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