The Quest for the Ultimate Cup of Coffee: Fresh is Best

We all know fresh is better for food, but what about coffee? Coffee is a thousand year old beverage and a $120B/year global industry but we’re still learning the science of coffee. Recent scientific studies have shown that fresh is best for coffee and that there are clear scientifically measurable markers to prove this.

For us this started with tasting the coffee we were making and noticing that it seemed to more aromatic and flavorful than we could get at even the best cafes in San Francisco. We at Seva Coffee build a machine that starts with raw green coffee beans and roasts, grinds & brews every cup personalized to you (see the video at So we started investigating the scientific literature of coffee and came across a series of studies on coffee freshness. It turns out this is a recent area of study in the coffee industry and not well known even in the industry.

To understand freshness, we have to take short detour into coffee chemistry. The roasting of coffee creates over 800 different chemical compounds. One of the compounds created during roast is methanethiol (MeSH) which is highly reactive. As coffee ages, methanethiol reacts to form dimethyl disulfide (DMDS). This is a good measure of coffee aging because there is no DMDS to start with in coffee and only appears as the coffee ages. So scientists created a ratio of MeSH/DMDS and measure this ratio as coffee ages starting from the moment the roasting of coffee ends. For a more detailed discussion of this topic, we suggest checking out Chapter 14 in this book.

Typical form of coffee freshness loss curve.

So how does this coffee aging curve look? Here’s an example. The horizontal axis is time starting from the moment the roast ends and the vertical axis is the ratio MeSH/DMDS starting at 100% at the moment the roast ends. As time passes, you can see the ratio drop dramatically. In fact there can be a 40% decrease in freshness in just the first few hours after roasting (we’ve taken data from the original scientific publications and combined them onto one graph to make them easier to read).

Coffee freshness hasn’t advanced much in a century.

Let’s take this one step further and look at how different types and packaging of coffee stack up. The chart starts with 100% at the top and zero at the bottom with areas shown for roasted whole bean, aluminum foil capsules, plastic capsules, and ground coffee in a tin (ranges are due to variances in packaging, age, handling, storage temperature, etc). Seva Coffee is at the top since the cup is made immediately after roasting and thus no decay. If you step back and look at this, the last 117 years of coffee technology research with billions of dollars spent has not been about the coffee at all — it has been about packaging technology trying to preserve what cannot be preserved. To put this in perspective, Hills Bros in San Francisco invented the first sealed tin with roast and ground coffee in 1900. If you happen to be in San Francisco, there is a statue and plaque commemorating this event in the courtyard of the Hills Bros building along the Embarcadero. So in the last 117 years, coffee technology has progressed from that tin to today’s aluminum capsules and plastic capsules that still don’t work and cause untold environmental pollution. These antiquated approaches have reached their limit. There must be a better way.

We start with raw green coffee beans that last years without spoilage and roast, grind & brew every cup personalized to you — the freshest cup of coffee possible with zero freshness decay. We use a compostable capsule made with natural plant fibers so there is nothing to clean and no waste. We changed our perspective on coffee, broke conventional wisdom and nearly a dozen new concepts suddenly became possible and we set out to build them all. Stay tuned, join us at and see what’s possible in coming weeks.