3 October 2023

… and there’s a Pittsburgh connection.

When you make coffee, what do you do with the spent grounds? Some people compost them at home or use them as fertilizer. You can even turn them into an insect repellent or natural cleaning scrub. But most of us just throw them away.

When Michael Rivera was in grad school at Carnegie Mellon he spent a lot of time at Arriviste Coffee Roasters in Shadyside. At the time, Arriviste paid a service to collect their coffee grounds but the service stopped during the pandemic and the spent grounds piled up.

Rivera was working on 3D printing technology and saw how to solve two problems at the same time: (1) Reuse coffee grounds instead of throwing them away and (2) Reduce plastic use in 3D printing.

The vast majority of 3D printing machines use thermoplastic to make new objects by melting it and reforming it with the print head.

It can take a lot of plastic to make an object, particularly a large one.

Rivera is now a postdoctoral researcher at University of Colorado Boulder where he further fleshed out his idea of using spent coffee grounds instead of plastic.

Rivera and colleagues mix dried spent coffee grounds with two common food additives — cellulose gum and xanthan gum — and then mix in water.

“You’re pretty much shooting for the consistency of peanut butter,” Rivera said.

You can’t load that ooze directly into a 3D printer. First, Rivera does a little jury-rigging, modifying a printer with plastic tubes and a syringe filled with coffee paste. When dried, the coffee grounds material is about as tough as unreinforced concrete.

— Science Daily: 3D printing with coffee: Turning used grounds into caffeinated creations

Here’s a coffee-based 3D print, photo embedded from the Ars Technica article.

The resulting objects are completely recyclable.

“You can make a lot of things with coffee grounds,” River said. “And when you don’t want it anymore, you can throw it back into a coffee grinder and use the grounds to print again.”

— Science Daily: 3D printing with coffee: Turning used grounds into caffeinated creations

Here’s how Rivera and his team make 3D objects with coffee grounds.

Read more about the project in Ars Technica: Don’t throw out those used coffee grounds—use them for 3D printing instead and the published study in July 2023 in the Association for Computing Machinery.

p.s. Does the reuse of coffee grounds sound familiar? I blogged about it a few weeks ago but forgot to mention it until Jennie Barker made the comments below.

(photos from Wikimedia Commons, Kate St. John, Arriviste Coffee Roasters Facebook banner, and embedded photo from Ars Technica; click on the captions to see the originals)

24 September 2023

A new study from Australia has found that adding used coffee grounds to concrete makes it 30% stronger!

To prepare coffee as a concrete additive, the study team collected spent coffee grounds and turned them into biochar in a low-energy process without oxygen at 350 degrees Celsius.

Not only did coffee make the concrete 30% stronger but the already used grounds did not end up in a landfill, a significant savings since the world’s coffee drinkers create 10 billion kg (11 million tons!) of spent coffee every year.

If the idea catches on, coffee waste will reduce the need for sand in concrete …

… which will reduce the need to mine so much sand, a finite resource.

Will piles of sand at concrete plants be replaced by piles of biochar coffee? Imagine what it would smell like at a cement plant, like this one along the Parkway East near Uptown, satellite view below.

Google satellite view of Heidelburg Materials Concrete / Lindy Paving, 2nd Avenue, Pittsburgh

Read more about this innovation at Science Daily: Coffee Offers Performance Boost for Concrete.

I hope it catches on.

(credits in the captions)

25 May 2023

Call me crazy. Or maybe old-fashioned.

Whenever I go birding I make a list — on paper — of the birds I see using the four-letter code for each species. When I get home I type the paper list into eBird. This paper list became this checklist.

Why don’t I just enter the birds directly into the eBird app on my phone? Unfortunately I learned long ago that if I look at my phone in the woods I start to read email, respond to text messages, check the news … and suddenly I’m not birding anymore and I’ve got a whole new set of Things To Do that I didn’t need to trouble with yet. So to keep myself focused I write a paper list.

The codes are easy to remember (see the rules here) except where the rules resolve to the same thing for two or more birds. The overlap codes are the ones I forget:

• Bay-breasted warbler (should be BBWA, I wrote BAYB)
• Blackpoll warbler (should be BLPW, I wrote BLKPOLL) and
• Blackburnian warbler (should be BLBW, I wrote BLKBUR).

I remembered these, though:

• BAOR = Baltimore oriole
• CHSP = Chipping sparrow
• MAWA = Magnolia warbler

My list should have been:

Where did the codes come from? If you’ve read this far you might be curious.

(photo by Kate St. John)