Our Heavy Metal Manifesto

We wrote this article to share our perspective on the topic of heavy metals in chocolate, to offer some research for further reading, and to help you feel confident in choosing chocolate for you and the people you care about.

A quick look at our standards:

• Each shipment of cacao is tested so that we know what is in it
• We look for cacao origins that consistently…
  • has lead levels below the limit of detection
    
  • has cadmium levels below European Union standards

We keep our standards high because we want to enjoy our chocolate – and share it – without any concerns. There’s enough things to worry about when running a chocolate factory, and we don’t want heavy metals to be one of them.

That’s the short story, and you can keep reading for the unabridged version that really drills into the two most important metals for chocolate lovers to be aware of: lead and cadmium. 

Don’t hesitate to reach out if you have any questions on anything in this article or our worldview on this important topic.

- Logan & Lauren

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Overview

Heavy metals are elements that have a density at least five times greater than water. These elements are found in the earth’s crust and are formed by volcanic activity, forest fires, or the weathering of rocks. Some heavy metals, like zinc and copper, are essential for the body to function, while others, like cadmium and lead, degrade the body's ability to function.

Because heavy metals naturally occur in the earth’s crust – and the soils that sit on the crust – many plants absorb trace levels as they grow, which means most food staples contain trace levels of heavy metals. For example, a 2012 study in Europe showed that people get their dietary cadmium from the following sources:

• 27% of dietary cadmium came from grains and grain products
• 16% of dietary cadmium came from vegetables and vegetable products
• 13% of dietary cadmium came from and starchy roots and tubers
• 4% of dietary cadmium came from chocolate products

Heavy metals are a part of life, and our bodies are skilled at managing both beneficial and toxic heavy metals effectively. From a health perspective, heavy metals become a problem when our diet provides more than just trace amounts.

What follows is a detailed discussion about the two most important metals for chocolate lovers – lead and cadmium – and how we think about and manage these metals as chocolate makers.

Lead

While lead naturally occurs in the Earth’s crust, cacao trees do not pick up lead from the soil as they grow. This means that if lead is present in cacao or chocolate, it typically originates from how raw cacao beans are handled and transported after harvest. A common source is cacao dried on surfaces that have accumulated lead-bearing dust. Beans dried near roadways, for example, can pick up trace amounts of lead left behind from decades of burning leaded gasoline. This “legacy lead,” which persisted long after the United States phased out leaded gasoline in 1996, is the same reason trace amounts of lead can be found throughout much of our food system today.

Cacao with lead contamination is a sign that the cacao may not have been well-cared-for during the post-harvest process. And because of that, lead is mostly found in commodity cacao and is much less common in the specialty cacao that we buy.

I recently looked at lab reports from 20 of the most popular speciality cacao origins. Of those 20 origins, just 3 of the origins tested positive for lead. One origin had 17 parts per billion (PPB), one had 20 PPB, and one had 33 PPB. For context on these numbers, the FDA says that most leafy greens contain between 10 and 40 PPB lead.

So 3 out of the 20 origins I reviewed tested positive for lead (15%), and all 3 that tested positive had lead levels that you would expect to find on leafy greens in our food system. My takeaway from this research was two things:

1. finding lead in speciality cacao is not common
2. when it is detected, it is at levels found in much of our food system

BUT… We still don’t like lead, and zero lead is better than 20 parts per billion. So we’ve decided to seek out origins that consistently test negative for lead, for two key reasons.

1. Lead in cacao can be a sign of a sloppy post-harvest handling process, and it makes us wonder if there are other things about the cacao that we don’t like: poor quality fermentations, inconsistent fermentations from year-to-year, poor shipping conditions, etc.
2. We don’t tolerate lead in other areas of our life. Lauren used to volunteer for the Montana Raptor Center and learned that lead poisoning (from lead bullet fragments in prairie-dog carcasses) is a key driver of raptor hospitalizations and deaths each year in the Northern Rockies. For this reason, when we hunt elk or deer, we use solid copper bullets that do not contain lead. 

We consider cacao to be “lead free” if lead levels are below the limit of detection using an Inductively Coupled Plasma Mass Spectrometry (ICP-MS) test. The threshold for detection on this test is typically 0.005 mg/kg or 5 parts per billion. We get lab test data from each shipment that we receive, and our happy to share this data with you.

Cadmium

The topic of cadmium in chocolate is quite different than lead. Like lead, cadmium is a by-product of volcanic activity. Unlike lead, cacao trees do naturally pick up cadmium from the soil as they grow. This is because cadmium easily dissolves in water and cadmium ions are similar in size to zinc and calcium ions - two important metals that plants take up through their root systems.

Cadmium levels from a given cacao origin will fluctuate from harvest-to-harvest, so each shipment needs to be tested. Factors like soil acidity and average tree age both impact how much cadmium cacao trees pick up from their soil. The European Union published cadmium limits in 2019, and because of that, there is a lot of research being down right now looking at how farmers can mitigate the amount of cadmium their trees pick up.

Because of the connection between recent volcanic activity and cadmium, cacao grown in Africa tends to have less cadmium in it than cacao grown in Colombia, Ecuador, or Peru, which are all places with recent - in geologic terms - volcanic activity. This also means that the cacao consumed by the peoples of Mesoamerica in 2,500 BC had trace levels of cadmium similar, to what we see today.

Before we go too far down the cadmium rabbit hole, let’s revisit the study from the beginning of this article that showed where our dietary cadmium comes from:

• 27% of dietary cadmium came from grains and grain products
• 16% of dietary cadmium came from vegetables and vegetable products
• 13% of dietary cadmium came from and starchy roots and tubers
• 4% of dietary cadmium came from chocolate products

And keep in mind that this was a study looking at Europeans, who consume more (and darker) chocolate that Americans do. So we would guess that Americans are getting less than 4% of their dietary cadmium from chocolate. BUT, like lead, there is no health benefit to having more cadmium in our diets, and we want to be mindful about how much cadmium is in our chocolate. This brings us to the question of figuring out how much is the right amount to tolerate.

In Montana and 48 other states, there are no laws or guidelines governing how much cadmium can be in chocolate. California has cadmium guidelines through Prop 65, but we don’t love the methodology they used to define their limit. That’s because their current guidelines are from a 2001 study that looked at a 1981 study on lab mice.

The European Union established new cadmium limits in 2019. Those guidelines allow 0.80 mg/kg cadmium in 70% dark chocolate. 0.80 mg/kg is equivalent to 8 parts per 10 million, and thinking back to our days-per-year analogy, this can be represented as 8 days per 27,300 years. Most of our origins come in well below this threshold, and in 2025 our Classic Dark chocolate had 0.23 mg/kg of cadmium - roughly 1/4 of what is tolerated by the EU in 70% dark chocolate.

We think even the European Union limits are extremely conservative, but we use them as a guide post so that we can enjoy our chocolate and share it with high-risk friends (pregnant women and young children) without having to worry about it.

Where the rubber meets the road

Below is an e-mail that I recently sent to an import partner letting them know what we are looking for. Hopefully this provides from context on how this all works in practice.

Important to note when reading this: fair-trade certifications are kind of like minimum wage - it’s the bare minimum from an ethical perspective and we want to pay farmers better-than-fair-trade prices for exceptional cacao. This is why I say in the email below that the cacao doesn’t need to be fair-trade certified but that we do want to understand the economics for farmers growing cacao that we buy.

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Email to import partner, 11/4/2024:

We are looking for a Colombian and Mexican origin that:

1) is fairly traded — it doesn't need to be fair-trade certified, but we want to understand the supply chain and economics for the farmers involved to make sure it is ethically traded

2) consistently tests negative for lead

3) consistently comes in below 0.8 mg/kg for cadmium

Look forward to learning about your origins and how we might be able to work together! 

Logan

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You might have noticed I used the word “consistently” in this message. As we noted, cadmium levels will fluctuate from harvest-to-harvest, so we want to work with origins that consistently come in below the E.U. standard. If one of our favorite cacao origins comes in above 0.8 mg/kg for a given harvest year we don’t want to reject that origin all together — we want to be thoughtful about how we use it that year and we can blend it with lower cadmium origins to keep supporting those farmers.

• As we noted in the section covering lead, the threshold for lead detection in these lab tests is just 5 parts be BILLION. So, for example, if a cacao origin that consistently tests negative for lead shows up one year with 12 parts per billion lead, we don’t want to reject that shipment or that origin. We want to understand how that lead level compares to rest of our food system, and then make an informed decision from. This is one topic where the context for these numbers is essential to making informed decisions.

Conclusion

We wrote this article to share our world view on the topic of heavy metals in chocolate, provide some research for further reading, and to help you determine if our chocolate is a good fit for you and your family.

Here's a recap of where we stand:

• Each shipment of cacao is tested so that we know what is in it
• We look for cacao origins that consistently…
  • have lead levels below the limit of detection
  • have cadmium levels below European Union standards

Let us know if you have any questions about what’s covered here, we think this is an important topic and are happy to discuss. 

Take care,

Logan & Lauren