If you’ve ever bought Abbots brushable glazes, you’ve probably also seen Universal Medium advertised for sale alongside them. Maybe, like me, you’ve also wondered what Universal Medium actually is - and what it’s for! Let’s find out together!

What is Universal Medium?

Universal Medium is a foundational component of Abbots brushable glazes.

When you reach for your favourite jar of Abbots brushable glaze, it can feel like you’re holding a jar of mysterious liquid you don’t quite understand. All you know is that it's your favourite and makes all your glazing dreams come true. 

But let’s stop for a moment and peel back that mystery.

When you crack open your favourite jar, what you’re holding isn’t magic.

It’s a precise, chemically balanced blend of dry glaze ingredients suspended in Universal Medium. 

In other words, Universal Medium is a foundational component of Abbots brushable glazes - it’s the liquid component of every jar!

Universal Medium gives Abbots brushable glazes their unique properties

A carefully formulated mix of water, gelling agent, dispersant, and biocide, Universal Medium is what gives Abbots brushable glazes their unique properties. 

Let’s dig a bit deeper into what that actually means. 

UM makes glazes brushable

For a glaze to be brushable, we need it to dry slowly once applied. 
Of course, we don’t want it to take too long to dry - just long enough for us to create long, even brushstrokes and smooth them out before applying the next coat. Because it contains gelling agents, Universal Medium slows down the absorption of water into your bisqueware, affording you a window to control glaze coverage and blend brush strokes before they dry.

UM allows us to layer

Part of the excitement of brush-on glazes is layering them with other brush-on glazes. Let’s be honest - that excitement is why we’re all here in the first place! Not only do we love to layer different brush-on glazes together to create new effects, but we also like to apply them in multiple coats to control thickness. To build up all these coats and layers without risk of peeling or crawling, we need each coat of glaze to create a strong bond to the coat underneath it. Universal Medium has been designed with this in mind, using binders or ‘hardening agents’ to glue successive coats to one another - leaving you to layer like a Queen.

UM keeps our brush on glazes suspended

If you've ever opened a bucket of dipping glaze, you’ll notice that the glaze particles settle to the bottom over time, leaving a layer of water at the top. In contrast, when you open a jar of brush-on glaze, this just doesn’t happen. What’s the secret? By using Universal Medium as the liquid portion, the glaze particles remain evenly suspended, ensuring you open the lid to a homogenous liquid every time.  

UM makes our glazes thixotropic

Brush-on glazes spend a fair amount of their lives sitting on shelves. And while they’re sitting on those shelves, they don’t exist as a runny liquid in the jar, but as a gel-like substance. If you were, for example, to grab a jar off the shelf right now and open the lid, you’d be greeted by a thick, viscous, honey-like material inside. This dynamic of brush-on glazes can throw people off the first time they see it - it can be hard to imagine brushing a thick gel. What we’re seeing here is an example of thixotropy. Now, before you run away screaming at this ‘sciency’ piece of jargon, let’s break it down - it may be more familiar to you than you think. Think of a jar of mayonnaise, or a bottle of tomato ketchup. At rest, the material sits thick and unmoving. Shake it, stir it, or even whisk it up — and it becomes noticeably more fluid. Stop agitating, and it stiffens up again. That’s thixotropy. Abbots glazes behave in the same way - and that’s largely due to Universal Medium. The thick material in the jar isn’t the working consistency. It’s the resting consistency. When we introduce ‘shear stress’  to the glaze - that is, when we shake up the jar, it becomes a creamy, brushable fluid.

Universal Medium isn’t just a foundational glaze ingredient. It's a control tool.

If you’ve read this far, you might be thinking, “That’s all very nice, but why should I actually care?”

It’s a good question. 

Here’s the answer:

Universal Medium isn’t just a foundational glaze ingredient - it’s also a fine-tuning tool that lets you adjust glaze viscosity, flow, and absorption rate to exactly how you like it. 

What this can mean for you:

It enables you to fine-tune glaze consistency

Because Universal Medium is the liquid foundation of Abbots glazes, it can be used as an additive to fine-tune their consistency. 

That is, by adding a few drops of Universal Medium to your glaze, you can nudge it into a slightly more fluid direction. 

The key to remember here: Universal Medium is a control tool, not a thinner.

Unlike water, it doesn’t dilute or change the glaze — it simply allows you to adjust lubrication, flow, and brushability. Even small amounts - we’re talking drops - make a noticeable difference. 

It enables precision in layering

As we’ve already noted, we’re all here for the layering - we love to layer different glazes to create new effects. One, perhaps overlooked, use of Universal Medium is as a precision tool for layering.

You can use Universal Medium within or between layers to control thickness — from full coats to very thin, wash-like applications. You can even use it on its own as a semi-penetrable resist, effectively reducing the impact of each succeeding coat. 

It revives stiff or dried-out glaze

If you’ve ever had a jar of glaze that’s been sitting at the back of the shelf for a while, you might have wondered how to revive it if it has become stiff and dry. The answer? You guessed it: a few drops of Universal Medium and a good shake will often bring it right back to life.

It overcomes the draggy brush problem

Some clay bodies and bisque firings produce a porous surface that absorbs glaze almost on contact. When this happens, your brushstrokes drag and dry almost as fast as you make them, leaving you with a glaze application made up of short, choppy, feathered marks instead of long fluid bands. 

This is where Universal Medium can really earn its keep. By adjusting the first coat of brush on glaze with Universal Medium, we’re able to slow the rate at which that glaze absorbs into the bisqueware. In short, Universal Medium gives you a longer working time — long enough to lay down smooth, even bands and blend brushstrokes before they set.

The Takeaways

We started this article with two key questions. Firstly, what is Universal Medium? And secondly, what on earth is it for?

Let’s summarise!

Universal Medium is a foundational component of Abbots brushable glazes and is what gives them their unique properties. Universal Medium slows drying just enough for a smooth, even brush application; lets us layer glazes without risk of peeling or crawling; keeps glaze particles evenly suspended in the jar; and gives our glazes a gel-like quality at rest that becomes fluid when agitated (thixotropy).
Universal Medium isn’t just a foundational glaze component — it’s also a control tool that lets you adjust how your glaze behaves and applies. Universal Medium lets you fine-tune glaze consistency and flow without diluting it; achieve precision when layering; give new life to stiff or dried-out glaze; and finally, overcome the absorbent bisque problem.

Join Abbots Glaze on socials!

For glaze process tutorials, tips and inspiration, join us on Instagram.

To connect with fellow Abbots Glaze enthusiasts and find inspiration for your next project, join the Abbots Glaze Lab Facebook group. 

About the author:

A self-confessed glaze nerd, Amy is a content creator for Abbots Glaze on a mission to get people excited about glazing! When she’s not making reels or testing new glaze recipes, you can find Amy making pots in her pottery studio, Palmerston North. You can follow Amy’s work on Instagram @fettlepotterynz