Caramel Espresso Stout
Today was THE most technical brewday I have done. The week leading up to it I was doing a lot of research on the caramel espresso stout – mainly on using the individual ingredients to get a perfect balance. I love espresso, I have it every morning for the last two decades and I make it myself. When I go to Starbucks I always get the Caramel Macchiato. Though remember the defunct Caribou Coffee shop on Market with the Turtle Mocha? That had a lot of caramel too that was super decadent. I wanted to reproduce this on a beer level…and since it’s now firmly stout season…
First, a little caramel chemistry!
Doing the research, I decided to be super authentic with home-made caramel. As a former polymer chemist, the chemistry of caramel is very interesting in itself. There is a lot going on and it’s difficult to control just due to the fluid viscosity and high temperatures.
Essentially, caramel is this:
- Heat induced decomposition of sucrose (disaccharide of fructose and glucose – C6 sugars). This is aided by an acid catalyst – I used lemon juice.
- Now these fructose and glucose sugars start to decompose into products like furans (nutty aroma), diacetyl (butterscotch aroma and flavor – this is usually a bad off flavor in beer) and a few other compounds.
- The individual sugars also start to assemble into oligomers – low molecular weight polymers. These oligomers are called caramelan (C12), caramelen (C36) and caramelin (C125).
It’s VERY important in making caramel to cut the heat at exactly the right time as when you pull it out of the oven, it will still be reacting as it takes awhile to cool down. Since my microwave is different than the person’s recipe, we had to pull it out every few minutes to check the color as the energy was different.
And now the espresso…
Espresso is very chemistry-like too and very technical. There is a lot of stuff going on to control to then make a smooth, good espresso. If things get out of control, you have too much bitterness.
Espresso is dependent on:
- Filter radius
- Steam pressure (water temperature)
- Water to grind ratio
- Grind size
- and most importantly, the contact time between the grounds and the steamed water. NO MORE THAN 30 SECONDS!
I decided to make the ‘good twin’ to my recent Amarillo IPA. The Amarillo IPA is ONLY GETTING BETTER on tap. It’s more of a malty, dark East coast IPA that is nearly a double IPA (DIPA). The Amarillo hop ages wonderfully.
I wanted the Citra IPA to have lighter body, a little less alcohol to make it solidy in the IPA category and more of a citrusy hop profile. As opposed to the darker Amarillo IPA, I will be filtering the Citra IPA.
I used the Hop Rocket for this with lot’s of Citra hop pellets and whole hops. Again, IPA’s and using whole hops at the end of the boil are more difficult – if you don’t pumpout quick or cool quick, those hops will start turning bitter and will over-bitter your beer. We did a lot of stuff to try to mitigate this as pumping hot wort inline through 4 oz of whole hops is usually problematic.
Thanks Jesse! It was more of a solo brewday with us and he was a huge help. It was a long day…7:30am to 8pm for two batches – NOT including cleanup. But he got to take home our newest Cascade Session IPA, yum!
We also evaluated a few commercial pumpkin beers and drank our newest Session IPA.
More reading on Espresso chemistry
More reading on Caramel chemistry