Build Your First System Dynamics Model – Agave Aging Chains in SimLin

Picture @EspinaDoradaMezcal

🌿 A Taste That Asks Permission

María stands in silence beside a wild agave, machete in hand. Before she makes a single cut, she places her fingers on the leaves, closes her eyes, and whispers something—not for the tourists, not for the brand—but for the earth and the spirit of the plant.

Then she begins.

What ends up in your glass began decades ago—not just in soil and sun, but in a system of trust, ritual, and ecological timing.

But what happens when demand outpaces patience? When bottles move faster than the plants can grow? When culture becomes commodity?

🌱 Experiment With Us:

Build Your First System Dynamics Model – Agave Aging Chains in SimLin

This month in Experiment With Us, we invite you to take your first steps into the world of System Dynamics — hands-on, free, and beautifully simple. Using SimLin, a browser-based tool, we'll model how different Agave species move through their life stages: from tiny sprouts to ready-to-harvest plants for sacred Mezcal production.

You'll see how time, growth, and sustainability weave together into a living system. (And don’t worry — you’ll be guided every step of the way.)

🌟 Step 1: Create Your SimLin Account

1. Go to https://simlin.com/.

2. Click Log In at the top right corner.

3. Select Create an account.

4. Fill in your email and password.

5. Once inside, click New Model to start your first experiment!

🌿 Step 2: Understand the Story We're Modeling

In the sacred world of Mezcal, different Agave species grow at different speeds:

• Espadín takes about 8 years to mature.

• Tobalá can take 15–20 years!

We'll model this life journey of agaves in three stages:

• Baby Agaves → Maturing Agaves → Harvest-Ready Agaves

Each stage will have a delay representing how long it takes an Agave to grow.

⚙️ Step 3: Build Your Aging Chain

A) Create Three Stock Variables

Click the Stock tool (the square icon).

Place three stocks on the canvas:

• Baby Agaves (units: plants)

• Maturing Agaves (units: plants)

• Harvest-Ready Agaves (units: plants)

B) Connect Stocks with Flows

Click the Flow tool (arrow line).

Draw:

• Grow: from Baby Agaves → Maturing Agaves

• Mature: from Maturing Agaves → Harvest-Ready Agaves

Add:

• Planting inflow into Baby Agaves.

• Harvesting outflow from Harvest-Ready Agaves.

C) Create Converters (Variables)

Instead of typing constants into flows, we'll create converters (small circles) that define time delays as variables, making our model easier to explore.

Add three converters:

• Planting Rate (units: plants/year)

• Time to Maturing (units: years)

• Time to Harvest (units: years)

And connect them:

• Planting Rate → Planting flow.

• Time to Maturing → Grow flow.

• Time to Harvest → Mature flow.

🔢 Step 4: Define the Equations and Units

Click each element and set the following:

Planting Rate = 10 Units: plants/year Note: Planting 10 agaves per year.

Planting (Flow) = Planting Rate Units: plants/year Note: Inflow into Baby Agaves.

Grow (Flow) = Baby Agaves / Time to Maturing Units: plants/year Note: How quickly Baby Agaves move to Maturing, based on maturing time.

Mature (Flow) = Maturing Agaves / Time to Harvest Units: plants/year Note: How quickly Maturing Agaves become harvest-ready.

Harvesting (Flow) = Harvest-Ready Agaves / 1 Units: plants/year Note: Harvest-ready plants leave the system in 1 year.

Time to Maturing = 8 Units: years Note: Espadín example: takes 8 years to mature.

Time to Harvest = 7 Units: years Note: 7 more years after maturing to be fully ready.

✅ Tip: Always check that units match. For example: if "Baby Agaves" is in plants, and "Time to Maturing" is in years, then "Grow" is plants/year — it makes sense!

🕰️ Step 5: Set Simulation Settings

Before running the model:

• Click the gear icon (Model Settings).

• Set:

Why?

• Final Time (20 years): Agave life cycles are long! A 20-year horizon helps you fully see planting, growing, and harvesting cycles.

• Time Step (DT = 0.25 years): DT controls how often the model "updates" calculations. A smaller DT (like a quarter of a year) makes simulations more accurate — important for biological growth systems.

✅ Think of DT as how often you look at the system. Smaller DT = clearer and smoother changes.

📈 Step 6: Run and Play

• Click Run (▶️).

• Watch how Baby Agaves mature and flow toward harvest over the years.

• Experiment:

Notice how different Agave species create very different futures for a farm or a community.

📦 Archetypes in Nature

Archetypes are universal system patterns that show up across different places, times, and stories.

The Aging Chain is one of them:

• New things enter (birth, planting, apprenticeship).

• They grow and transform through different stages.

• They eventually exit (harvest, mastery, retirement).

You’ll find Aging Chains in forests, communities, careers — and even mezcal traditions.

When you model an archetype, you model something timeless.

🌱 ➔ 🌳 ➔ 🌲 "From seed to elder — aging chains shape life across time."

🧵 Final Reflection

Modeling is an act of honoring complexity. With just a few variables, you've captured the living rhythm of a centuries-old tradition. 🌿

Imagine:

• How climate change could shift these cycles.

• How overharvesting could collapse a species.

• How mindful planting could sustain sacred systems for generations.

This is the power of System Dynamics — and now it's in your hands.

📩 Share Your Journey!

If you build your model (or tweak it in a cool way!), take a screenshot and share it with us! We'd love to celebrate your first experiment!