The Mystery of Mash Thickness: Does Ratio Really Matter?

Good morning. In a blow to the craft brewing scene, Duck Rabbit Brewing is closing after 20 years of operation. The North Carolina brewery known for it’s dark beers, including it’s famous Milk Stout cited that the closure was due to rising costs and shifting consumer preferences.

-Brandon Copeland

The Mystery of Mash Thickness: Does Ratio Really Matter?

You’ve dialed in your grain bill, timed your hop additions, and even fussed over yeast health. Yet one variable often flies under the radar: mash thickness - the ratio of water to grain during your mash. Some brewers swear by ultra-thin mashes for easy runoff, while others champion thick mashes for enhanced body. So, does mash thickness actually change your final beer, or is it just another number to obsess over?

What Is Mash Thickness, Anyway?

Mash thickness is typically expressed in quarts of water per pound of grain (qt/lb).

• Thin mash: around 1.5 - 2.0 qt/lb

• Medium mash: roughly 1.25 qt/lb

• Thick mash: 1.0 qt/lb or less

Thicker mashes feel like porridge; thinner ones are more soup-like. But beyond mouthfeel, why should brewers care?

The Case for a Thin Mash

Pros:

• Easier lautering: More free water means grains stay freer-flowing, reducing stuck sparges.

• Faster conversion: Wort circulates more readily, potentially speeding up enzymatic activity.

• Predictable efficiency: Many calculators and efficiency charts assume a thinner mash.

Cons:

• Diluted enzymes: With more water, enzyme concentration per grain mass drops—could slow conversion in marginal malts.

• Lighter body: If you love a big, chewy malt character, a thin mash might feel too crisp.

Some brewers running simple infusion systems default to thin mashes “because that’s what my gear handles best.” But does “what your gear handles” align with “what your beer needs”?

What About a Thick Mash?

Pros:

• Fuller mouthfeel: Less dilution can translate to a richer, creamier beer body.

• Flavor intensity: Concentrated wort can carry more malt depth and color.

• Historic accuracy: Many traditional European mash schedules used very thick mashes long before modern equipment existed.

Cons:

• Lautering headaches: Thick mashes can compact and slow sparge runoff—especially in brew-in-a-bag setups.

• Hot spots: Heat transfer can be uneven in a porridge-like mash, risking temperature swings that affect enzymes.

For style-centric brewers chasing old-world lagers or robust porters, that extra body might be worth wrestling with a stubborn mash tun.

What Does the Research Say?

Studies show that, given enough time, both thin and thick mashes can achieve similar starch conversion—provided mash temperatures are accurate. Differences in fermentability and efficiency tend to be modest (often within a few points). But subtle shifts in sugar profile and mouthfeel can still be noticeable to discerning palates.

So… Is Mash Thickness Worth Dialing In?

If you’re chasing every last point of efficiency or a specific mouthfeel, experimenting with mash thickness could be enlightening. But if your brews are already hitting targets and tasting great, this might be a refinement rather than a revolution.

Sponsored by 1440 Media

The Daily Newsletter for Intellectually Curious Readers

Join over 4 million Americans who start their day with 1440 – your daily digest for unbiased, fact-centric news. From politics to sports, we cover it all by analyzing over 100 sources. Our concise, 5-minute read lands in your inbox each morning at no cost. Experience news without the noise; let 1440 help you make up your own mind. Sign up now and invite your friends and family to be part of the informed.

Join for free today!

Beer Trivia Question

🍺 What continuous mashing system, invented by Charles Saladin in the early 1900s, is known for using a thin mash and mechanical stirring to improve lautering efficiency?

Read to the end to find out if you're right!

Brewgr Recipe of the Week
Lean Tree

We often highlight all grain recipes, but this is a solid, dependable pale ale that uses Dry Malt Extract. It uses one hop, the one that started it all for American pale ales, Cascade. You can’t go wrong with this one - you’ll essentially get a Sierra Nevada clone.

Credit: Kermando

Poll Results: Do You Mashout?

It doesn’t surprise me that this group overwhelmingly always performs a mashout - while it may or may not actually improve your beer, if there is a way you can optimize your beer (and you have temperature control) why not do it. To be honest, I normally skip the mashout and prefer just to allow my sparging to raise the temp up a bit at the end. However, I may start performing a mashout - I use an all in one brewing system and have temperature control, so why not?

And the Answer Is...

🍺 The Saladin mash (or Saladin box) system, which maintained a thin, well-agitated mash to optimize starch conversion and grain bed permeability.