Why Heat and Pressure Control Matter in Rosin Pressing

When pressing rosin, the two most important variables that need to be controlled for aside from material input are heat and pressure application. Rosin press heat and pressure ultimately dictate the flavor, quality, yield, and purity of rosin so precise control of these factors is critical to the creation of high quality solventless rosin. Without enough of either, the process of rupturing trichome heads and liquefying the resin they contain doesn’t occur properly. Conversely, too much heat can lead to resin degradation, terpene loss, and darkened color whereas too much pressure leads to bag blowouts. 

If you want to create the best rosin possible, having the right rosin press is necessary to learn how to control both heat and pressure like an artisan hashmaker. 

The Role of Heat in Rosin Pressing

First man discovered fire, and then much later engineered heated rosin press plates. Similar concept in the annals of inventions. Hashmakers need to apply temperatures that hover just below what it takes to boil water (generally 150°F at a bare minimum but 180°F to 200°F is advisable for most live ice water hash cultivars). 

Heat melts the delicate trichome head shell which is only about 1-2 micrometers thick, which then turns the resin they contain into a liquid state that allows it to flow through the filtration of a rosin bag.

With too low of heat, the trichomes will rupture under adequate pressure but you’ll just end up with a mismash of broken trichome shells, heads, and resin and not actual rosin. The liquefaction is essential for the entire process to happen quickly since heat, the magic ingredient, needs to be applied for the shortest amount of time possible to make great rosin.

Correct heat application affects all of the following variables and largely depends on exactly what biomass or type of material you are pressing, but having a high quality rosin press that provides accurate, consistent temperature to its plates is key to making great rosin.

• Rosin quality – too little heat means no rosin, too much heat means burned rosin that smells like popcorn or worse. 

• Flavor and aroma – many terpenes completely volatilize at high temperatures, thus sharply affecting rosin’s flavor and aroma.

• Color and bag appeal – high temperatures above roughly 210-220°F quickly darken rosin so that it’s less appealing and more amber or brown than light gold or creamy colors that consumers demand.

• Texture – higher pressing temperatures tend to create a sappier, stickier rosin whereas lower temperatures lead to budders and badders typically.

Not sure how much heat to use? This handy chart breaks down what we suggest, however results may vary so be sure to experiment to find the perfect amount of heat for your rosin. We suggest starting at a slightly lower temperature than you think you would typically expect for the first press of any material and then ramp up accordingly as needed.

Why Pressure is Essential to Pressing Rosin

When heat combines with pressure applied to a filled rosin bag, special things happen. Force is required to move the liquified resin through the filtration bag and off of the heated plates. Using the exact right amount of pressure though varies by material, rosin bag micron size, and total material weight. 

It takes a little bit of practice to nail your presses and although there are more things to consider than simply setting your temperature to the target setting and pressing your plates down, even your grandma could learn how to squish great live rosin quickly.

The first thing to ask yourself is what is your goal for each press? Is it to maximize yield, quality, or a mixture of both? Most hashmakers are looking to find a balance, because too much pressure can rupture the threads of the rosin bag creating a sticky, annoying mess or force unwanted plant material into the rosin. 

On the flipside, too little pressure means wasted yield and resin trapped in the bag that requires a second press, which means more time left on the heated surface of the rosin press’s plates. Putting your rosin bags through a pre-press mold helps a lot because it ensures your material is evenly distributed through the bag which sharply decreases the risk of a blowout when combined with double bagging. 

The best way to apply the right amount of pressure is to do so gradually, ramping up as rosin starts flowing which means less pressure within the bag. Here’s our list of tips the pros use to make sure they nail their rosin pressing pressure every time.

1. Use a pre-press mold and if pressing ice water hash or sift, double bag to be safe

2. Make sure your plates are at the set temperature before starting

3. Apply just enough pressure to start so that both plates are fully touching the top and bottom sides of the bag, then wait for at least 10-15 seconds for the heat to soak in before pressing harder

4. Gradually ramp up pressure on the bag with the goal being to have the full rosin extraction process complete within 1-2 minutes

5. Once most of the rosin has been squished out, hit it hard at the very end to get every last bit

There is a much wider margin for error when it comes to pressure when pressing flower compared to ice water hash. Typically with flower rosin you can just pretty much smash and go, but when live bubble hash is being squished, starting low and slow is essential. 

Why Plate Size Matters When Pressing Rosin

Rosin presses apply pressure in different ways and the size of the plates utilized are one of the most important aspects when deciding how much force to apply. Think about the tip of a pen: the actual surface area of a pen’s inky point is tiny, but even the average person will create somewhere in the ballpark of 10,000 PSI at the tip of their writing utensil when writing a simple note. 

Smaller plates apply higher pressure more quickly and by the same token, bigger plates distribute force over a greater surface area, meaning you need a higher tonnage cylinder to get enough force to maximize yield. PSI, or pounds per square inch, is calculated by dividing the amount of total available force (say, a 10 ton hydraulic cylinder) across the total surface area (with our 4x7 plates, 28 inches). That means there is about 20,000 lbs of force available, and with a 2.9” x 6” bag, that gives you 17.4” square inches.

In this example. at full force, that equals around 20,000 lb divided by 17.4 = 1,149 PSI. If you need to achieve higher pressure with flower rosin, use a slightly smaller bag to increase the overall available pressure. 

This table breaks down exactly how much pressure you should use depending on your material.

One sneaky factor that is easy to neglect is moisture content when it comes to deciding how much pressure to apply, and how quickly. Overly hydrated biomass whether flower or trichomes when heated can create additional pressure within the bag due to steam and water volume. The opposite is true for very dry material, where you might need to go even higher on the pressure scale to get an ideal yield. Adjust accordingly. 

How to Evaluate a Rosin Press’s Heat and Pressure Features

The science behind rosin pressing is fun to analyze, but what really matters is where the rubber meets the road with how well a rosin press can control both heat and pressure. The most important features to evaluate when selecting whether a rosin press can do what you need it to are listed here.

1. What's the use case for your rosin press? Is it commercial, high volume pressing or just for fun at home? 

High quality commercial rosin presses offer superior heat control and ultra precise pressure application. Don’t be fooled by extremely expensive options however, because there are only so many bells and whistles that you need. There’s a reason more hashmakers trust Lowtemp for their rosin pressing needs than any other brand, and that’s because our presses offer the perfect blend of features, heat control, pressure application, and price point. 

2. Does the press you’re interested in mention things like platen control, high quality thermocouples, and recipe development?

If not, you might be wasting your time even with a budget press. Thermocouples are the devices that are installed into the rosin press’s plates to apply heat evenly, which is crucial to making great rosin. Uneven heat or pressure application both lead to poor outcomes. Also, having a user interface that isn’t completely analog is important to create repeatable recipes for different cultivars and material types.

3. How much pressure does the rosin press offer?

In the end, having more available pressure is important even if you rarely use it to its full capabilities. As solventless processing has matured as an industry, more artisan hashmakers have discovered that additional pressure than they once used is imperative to their bottom lines – too low of pressure means wasted rosin and lost profits. For most users, 10 tons applied with reliable hydraulics is the perfect amount.

4. Can the rosin press’s system scale as your throughput needs grow?

If you’re planning to press at a licensed lab or in a caregiver scenario, investing in a rosin press system that scales with your needs is essential. That’s why Lowtemp offers its industry leading Medusa Systems, which allows your operation to add more presses as your order volume scales. Simply tack on another press with the same hydraulics double, triple, or even quintuple your throughput with ease using our simple to install Medusa configurations. 

Tying Rosin Press Heat and Pressure Together

Both heat and pressure play different but indispensable roles when it comes to pressing rosin. The general objective of any press is to get the maximum yield at the lowest necessary temperature as quickly as possible, which requires balancing all of the factors we covered here. Time, heat, pressure, material, filtration bag micron size, and so on need to be accounted for, but once you get the hang of it, pressing rosin like a pro is simple. 

If you need help selecting the right rosin press or even building out a turnkey solventless lab, our experts have you covered. More hashmakers trust Lowtemp than any other solventless equipment brand, so contact us today for your free consultation.