Bubble Hash vs Full Melt vs Rosin: What’s the Difference?

on January 11, 2023

Navigating the world of solventless hash can be confusing, as there are many types of extracts available in the market. Between Bubble Hash, Full Melt, and Rosin, it’s easy to get lost in all the different options – especially when some terms are used interchangeably even by experienced professionals!

Learn the difference between these three types of solventless hash options below, so you can choose the option that is right for you.

Bubble Hash

Bubble hash or ice water hash is created through a method known as agitation. Ice water makes trichomes brittle, since they’re not water soluble they break off and can be collected via screen. The trichomes are poured and filtered through micron bags and placed onto parchment paper, then freeze-dried to preserve flavor and freshness.


Full-melt refers to high-quality (5 or 6 star) bubble hash. When heated in a nail or banger, full-melt will remain light in color and puddle up as the membranes of the trichome heads are broken down, combining together into one resinous “puddle.” There should be no plant residue once Q-tipped. It is important to note that full-melt is not an easy or even guaranteed product to extract. To be successful, the process requires premium starting material (certain cultivars have higher success rates) as well as careful extraction techniques.


Rosin is the resulting product of heat and pressure application from bubble hash. Some people argue rosin could be considered full-melt hash if it melts on contact and leaves no charred plant matter behind, however, the term full-melt is intended to distinguish unpressed hash (resin) that is free of plant matter. Much of the higher end rosin offerings will use full-melt hash as their starting material.

Hash Star Ratings

The star rating system for hash can be a handy guide when it comes to selecting quality solventless concentrates. The ratings are based on the agitation extraction process, and provide valuable insight into different hash products. From six-star full-melt to one-star food grade hash, take a look at the breakdown in the table below and choose what’s best for you.

1 Star: The lowest quality hash, typically more than 50% plant matter and “unmeltable.” Plant matter content in one star bubble hash makes dabbing undesirable and ineffective. Typically, 1 star bubble hash is used in edible preparations and not sold as a standalone product for consumption.

2 Star: Similar to 1 star, 2 star bubble hash is low in trichome stalk and head count, while high in plant matter. Also used in edible production, you may see 2 star being sold in the form of “Bubble Blunts” as well.

3 Star: Enhanced micron filtering begins to kick in at the 3 star stage, with much less organic plant matter than 1 or 2 star. There are still smaller plant particles within 3 star bubble hash, but at this stage it is more trichomes than debris. Still not quite desirable to dab, 3 star bubble hash is often used as a bowl-topper or pressed into rosin.

4 Star: Often referred to as half-melt, 4 star bubble hash nearly reaches a full-melt consistency but falls short with residual plant matter still being in the mix. 4 star and half-melt is sold typically under the name “Bubble Hash” on dispensary shelves and is used for bowl-topping. It can be dabbed, but extractors will press it into rosin for best dabbing results.

5 Star: Entering full-melt territory, quality 5 star bubble hash should only contain trichome heads and stalks. Dabbing 5 star will leave minimal residue on your banger and bubble/melt fully with a rich, flavorful consumption experience. Many high-end rosins are pressed from 5 star bubble hash.

6 Star: If all the conditions line up and an extractor can get their hands on premium starting material, 6 star bubble hash, AKA full-melt, is possible through careful extraction. This is the cream of the crop, the small portion of a bubble hash yield that is nearly all trichome heads rich with cannabinoids and essential oils. When dabbed properly, 6 star should leave no residue on your banger and wipe away clean with a Q-tip. Many claim to offer 6 star products but that is not always the case. Check the melt quality to determine the actual star rating. Most “persy” and “premium” rosin varieties come from 6 star bubble hash.

Ready to go solventless? Take a look at our current medical cannabis products or, better yet, stop by in person!

Robyn Lawler