Know your flow

Understand what you're consuming, how it's made, and why it matters.

What is THCa?

THCa — Tetrahydrocannabinolic Acid — is the raw, non-psychoactive compound found naturally in the cannabis plant. In its natural state it won't get you high. But when heat is applied through dabbing, vaping, or smoking, THCa converts to THC and becomes fully active. This process is called decarboxylation — and it's the foundation of how concentrates like rosin work.

Is THCa Legal?

THCa products are federally legal under the 2018 Farm Bill when derived from hemp and containing less than 0.3% Delta-9 THC by dry weight.

While THCa is non-psychoactive in its raw form, it converts to THC when heated.

Laws may vary by state, so customers should always check local regulations before purchasing.

Learn More about THCa

What is Rosin?

Rosin is a solventless cannabis concentrate made using only ice water, heat, and pressure. No chemicals, no hydrocarbons, no shortcuts. The plant's trichomes are separated using ice water into hash, then carefully pressed into pure rosin. What you get is the full expression of the plant — every terpene, every cannabinoid, completely intact.

Our Process

Rosin vs Resin

Rosin

Rosin is a solventless concentrate made using only ice water, heat, and pressure. Instead of relying on chemical solvents, the plant’s trichomes are separated mechanically and then pressed into oil. This helps preserve a clean, full-spectrum profile that stays closer to the original plant.

Resin

Resin is typically made using solvent-based extraction methods that pull cannabinoids and terpenes from the plant material. These processes are common across many concentrate categories and can be effective, but they rely on a different production method than solventless rosin.

READ THE FULL ROSIN VS RESIN GUIDE

What does “live” mean?

“Live” means the plant was frozen immediately after harvest, helping preserve more of its natural flavor and aroma.

What is a wash?

In solventless extraction, a “wash” refers to one full cycle of separating resin from the plant using ice water.

Fresh-frozen material is gently agitated in cold water, allowing the trichome heads to break free from the plant. That mixture is then filtered through a series of micron bags, separating the resin by size and quality.

Each wash produces multiple grades of hash. From there, we determine what becomes Select, Craft, Reserve, or Ultra Reserve based on the cleanliness, micron range, and overall quality of the output.

HOW ROSSLYN DEFINES A WASH

Now that you understand what a wash is, here’s how we apply it.

At Rosslyn, each wash is evaluated and categorized into distinct tiers, designed to give you a clear sense of quality, flavor expression, and overall experience.

SELECT WASH — MIXED MICRON

Balanced and approachable. Select Wash blends multiple micron ranges to deliver a full-spectrum experience with strong flavor and solid potency.

This is where most people start, consistent, enjoyable, and easy to return to.

Shop Select Wash

CRAFT WASH — REFINED RANGE

More dialed in. Craft Wash focuses on tighter micron ranges and cleaner output, resulting in better terpene clarity and a more expressive profile.

This tier is built for those who want more nuance in flavor and experience.

Shop Craft Wash

RESERVE WASH — TOP TIER

Our most selective output. Reserve Wash is chosen for exceptional cleanliness, standout flavor, and smooth melt.

This is where everything comes together, quality, expression, and refinement.

Shop Reserve Wash