Nov 16, 2023 · 30m · how-i-built-this
Literally unearthing a climate solution with Cody Finke of Brimstone
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gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
In this episode of 'How I Built This Lab,' host Guy Raz interviews Brimstone co-founder Cody Finke about revolutionizing the cement industry by replacing carbon-heavy limestone with calcium silicate rock to produce the world's first certified carbon-negative Ordinary Portland Cement.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. Guy holds 45.8% of the talking time here. How this is scored →
Guy as informed peer 4.3 Guest teaching 3.4 Guest disagreement 1.0 Guy pushing back 1.9
speaking balance: gold is Guy, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 17:56 Reframing product parity
Cody immediately interrupts Raz's question about whether their material is 'as good as' Portland cement by firmly stating that it literally is Portland cement.
Hardest push from Guy ▶ 23:33 Incumbent competitive threat challengeRaz presses Cody on what prevents massive multinational cement corporations like Cemex or Alamo from copying the technology and taking over the market.
Biggest teaching moment ▶ 9:24 Volcanic subduction and carbon cyclesCody educates Raz on how cement kilns replicate volcanic temperatures to artificially disrupt billions of years of geological carbon storage.
Guy holds their own ▶ 23:11 Citing specific California climate mandatesRaz demonstrates domain knowledge by detailing California's specific statutory targets requiring a 40% emission reduction by 2035 and net zero by 2045.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | Guy as informed peer | Guest teaching | Guest disagreement | Guy pushing back | Why |
|---|---|---|---|---|---|---|
| Early Ventures in Solar Toilets and Water Electrolysis | 4 | 2 | 1 | 1 | Guy Raz traces Cody's academic background at Caltech, noting the Gates Foundation recognition. Cody explains how economic friction made his solar toilet and water electrolysis projects commercially unscalable despite technical viability. | |
| Identifying Cement as the Core Chemical Decarbonization Challenge | 6 | 3 | 1 | 1 | Raz introduces parallels to Pat Brown and Impossible Foods along with global emission statistics. Cody explains how IPCC data led him to focus on industrial chemical process emissions, particularly cement. | |
| The Chemistry of Traditional Cement Production | 5 | 6 | 1 | 1 | Cody provides a deep chemistry breakdown of how heating limestone prematurely releases trapped geological carbon into the atmosphere. Raz connects the concept to melting Arctic permafrost carbon sinks. | |
| Sponsor Break: Miro Collaboration Platform and Listener Testimonial | 0 | 0 | 0 | 0 | Mid-roll commercial break featuring an advertisement for Miro collaboration software and a listener voice memo. | |
| Discovering Calcium Silicate for Ordinary Portland Cement | 5 | 5 | 2 | 4 | Raz questions why calcium silicate was not utilized historically and asks about product strength parity. Cody firmly clarifies that their material is exact Portland cement rather than an alternative substitute, detailing changing energy economics. | |
| The Carbon-Negative Process and Magnesium Byproduct | 4 | 4 | 1 | 2 | Cody explains the carbon-negative mechanism whereby the magnesium byproduct passively mineralizes CO2 from ambient air. Raz questions waste disposal safety and environmental risks. | |
| Mid-roll Break and Scaling Challenges Teaser | 6 | 4 | 1 | 4 | Raz cites California emissions mandates and legacy cement giants to challenge Brimstone on IP defensibility and quarry infrastructure lock-in. Cody outlines their multi-tier supply chain approach and long-term capital requirements. |
Statements from this episode (17)
Finke: Do-good technologies require an economic case to achieve scale
“Deploying these sort of do good technologies is not trivial because people don't just buy them and install them out of the goodness of their heart, or at least not enough. There needs to be a compelling economic case.”
Finke: Hydrogen is made from fossil fuels because it is cheapest
“We don't make hydrogen by splitting water today. We make hydrogen a different way from a fossil fuel, actually. And we do that because it's the lowest cost way to make hydrogen.”
Finke: Cement had the lowest decarbonization funding per ton of emissions
“One metric that was really interesting to me was the dollars invested in decarbonizing the product per ton of greenhouse gas emissions. And I couldn't really find anything lower than cement.”
Finke: Cement accounts for about 90% of concrete's carbon emissions
“And just to clarify the cement and concrete, concrete is the building material, and cement is the binder, the glue. And about 90% of the emissions come from cement.”
Finke: Fuel and energy account for 40% of cement emissions
“The first is you need to burn a lot of fuel because you need to use a lot of energy to make cement, and that's about 40% of the emissions in cement production.”
Finke: Most cement emissions stem from chemical breakdown of limestone
“And the majority of the CO two emissions from cement come from that chemistry for releasing the CO two from the rock.”
Finke: Structural failures and delays cost 10 to 100 times more than cement
“Because both structural failures and construction delays are way more expensive than the cement. They're like 10 to a hundred times more expensive.”
Finke: Slowing coal power and steel growth is driving up cement prices
“The current production of cement actually relies on the production of electricity and steel from coal. And both of those industries' growth have slowed. And That is leading to a domino effect where the price of cement has been rising.”
Finke: Calcium silicate cement will be lower cost at scale
“In the modern economy, we think that will be lower cost at scale.”
Finke: Decarbonized cement will not achieve quick global adoption unless it is Portland cement
“We don't think global adoption will happen if it's not Portland cement. Or at least it won't happen quickly.”
Finke: Brimstone's process can be carbon-negative even using dirty fuels
“The beauty of our process is that actually could be substantially lower carbon or even carbon negative under a wide range of energy sources, including the use of those dirtier fuels.”
Finke: Calcium silicate eliminates 60% of cement emissions immediately
“The calcium silicate rock, A, does not contain any CO two. So we eliminate 60% of the emissions just by using a different rock.”
Finke: Brimstone process yields magnesium waste that passively sequesters CO2
“It produces a magnesium-based waste product, and that magnesium-based waste product will passively sequester CO₂. Just sitting on the ground, it will react with CO₂ in the air to permanently sequester CO₂.”
Finke: Brimstone cement certified as chemically identical Ordinary Portland Cement
“So just this last July, we got a third party certification that we, the cement that we made passed the existing standard for ordinary Portland cement showing that it's chemically and physically identical to the conventionally produced product.”
Finke: Brimstone holds patents on producing Portland cement from silicate rock
“So the process is patented and the utilization of this rock to produce Portland cement is also patented. So another company would need to license or joint venture with us in order to make cement via this process.”
Finke: Brimstone commercial plant unlikely to be fully operational in five years
“So in the next five years, we will be working on building a first commercial plant. I think it's probably unlikely that it's, you know, fully operational.”
Finke: Global cement plants will probably grow to 5,000 by 2100
“So let's say a cement plant, a modern cement plant costs around a billion dollars, and there are 3000 of them today, and there probably will be 5000 by the end of the century, because we will need to develop the rapidly developing world, as well as transition …”