Check out my Instagram reel on this topic 👉here👈

If you've spent any time in the specialty coffee community, you've likely seen the "perfect" recipes: 20g of coffee, 300g of water, 30-second bloom, total draw-down at 3:00 minutes exactly.

We obsess over these numbers. We buy high-precision scales and expensive timers to ensure we hit them every single morning. But have you ever hit your "target time" perfectly, only to take a sip and find the coffee tastes hollow, bitter, or astringent?

This is a classic example of Goodhart's Law.

What is Goodhart's Law?

Named after economist Charles Goodhart, the principle states: "When a measure becomes a target, it ceases to be a good measure."

In coffee terms, we take a measure (like draw-down time) that is meant to help us track extraction, and we turn it into the goal itself. We start brewing to "hit the 3:00 minute mark" rather than brewing to make the coffee taste good.

The "Target" vs. The Taste

When we elevate a metric to a target, we often start making bad decisions to satisfy that metric:

1. The Time Trap: If your recipe says 3:00 minutes but your brew is finishing at 3:30, your instinct might be to coarsen the grind. But what if the coffee actually tasted amazing at 3:30? By forcing it to hit 3:00, you might under-extract the beans and lose the sweetness you were looking for.
2. The Bloom Obsession: We measure the "bloom" precisely, but Goodhart's Law reminds us that the gas release is the goal, not the 30-second timer. Some coffees need 45 seconds; others are ready in 20.
3. The Ratio Rigidness: A 1:16 ratio is a great starting point, but it isn't a law. If you refuse to move to 1:15 or 1:17 because "the recipe says 1:16," you're letting the measure dictate the experience.

How to Break the Law (and Brew Better Coffee)

To move past "brewing by numbers," you have to treat your metrics as data points, not destinations. Here is how to apply this to your daily ritual:

• Use your senses first: If the coffee tastes bitter, it's over-extracted. It doesn't matter if you hit your "target time" perfectly—the extraction was too high for those specific beans.
• Log the data, don't follow it blindly: Use your scale and timer to record what happened, then use that data to adjust your next brew based on flavor.
• Trust your gear: If you're using a solid entry-level burr grinder like a 1Zpresso Q Air or a Timemore C series, you already have the consistency you need. Don't blame the gear for a "missed target" if the taste is already there.

The Takeaway

Metrics are the map, but the flavor is the destination. Goodhart's Law reminds us that the scale is just a tool to help us find the "sweet spot" again tomorrow. If the coffee in your cup makes you smile, you've won—regardless of what the timer says.