How to roast and blend Robusta for espresso

#1: Post by **drgary** » July 3rd, 2018, 2:04 pm

MaKoMo wrote:... this discussion was about blending coffees for espresso in general and me struggling to roast robusta without that rubbery taste. Arnould explained us his approach. He just roasts the robusta (only quality washed-beans worked for him) and keeps them resting for quite some time after roasting in half-closed containers until they get really oily. At that point he roasts the other components fresh and mixes them with the (aged) robusta in the cooling bin. That way he gets a very smooth blend without any rubber taste.

The aging of robust before adding the beans to an espresso blend is what I heard also once for an Italian roast master. So it might just work, thus I will try this out myself.

I'm sharing this quote from Marko so that others can join him in his exploration. His comment originated in this thread:

Some pix from the Artisan Meetup #1

#2: Post by **TomC** » July 3rd, 2018, 2:43 pm

Pretty much my standard practice if I'm wanting to incorporate a robusta coffee. Roast, age 2 weeks separately, and only buy quality Indian robusta, which already lacks most of the burning tire stench.

#3: Post by **Beaniac** » July 3rd, 2018, 6:44 pm

This is me being quoted by Marko, [anonymized] asked us to host Marko in our roastery close to Amsterdam during WOC2018.

Marko mentioned he tried and failed often to incorporate robusta in to his blends.

So I explained what works for me. Source quality robusta, a Guatemalan in my case and hit it hard with heat to get it into rolling second. Age it in a container and then blend it into the rest of the beans hot when they come right out of the roaster. I love the hefty marzipan & banana smell that comes off the robusta after a few weeks of degassing/aging.

-I try to avoid natural robusta.
-I do it with monsooned malabar to as a robusta replacement when customers want a 100% arabica blend but don't want sacrifice on body.
-I don't go over 15%, most common 8-12% in traditional comfort espresso blends.
-I,ve cupped quality robustas which really wowed me in flavor but unfortunately some do tend to upset my stomach.

#4: Post by **another_jim** » July 3rd, 2018, 11:05 pm

I agree; robusta needs to be aged before use. Also, the crema from robusta never goes away, no matter how old it gets; no idea why.

However, I've had decent results dropping the robusta roasts at the beginning of the second crack, as long as you slow down the roast, so you can still roast out the rubber smell. This has worked for me especially when using natural or aged robustas.

#5: Post by **EddyQ** » July 7th, 2018, 10:40 am

Beaniac wrote:So I explained what works for me. Source quality robusta, a Guatemalan in my case and hit it hard with heat to get it into rolling second.

Hitting hard with heat is surprising to me. I've never roasted Robusta, but would have thought of hitting it with a profile similar to a low altitude grown Brazil, which is low heat. Are these Guatemalan robusta beans low altitude grown??

#6: Post by **Beaniac** » July 8th, 2018, 6:24 am

Robusta is typically more dense then arabica. The cracks come later (at higher temps) and you have to roast it darker (or deeper if you will) for heat to fully penetrate into the core of the robusta bean.