BIAB vs. Traditional Mashing: What's the Difference?

All-grain brewing means starting with raw grain instead of malt extract. But there's more than one way to do it. Traditional three-vessel systems dominated for decades, but brew-in-a-bag (BIAB) has become the method of choice for many homebrewers. Here's how they compare.

Understanding the Basics

Before comparing methods, let's make sure we understand what we're actually doing during the mash.

Malted grain contains starches. Enzymes naturally present in the malt (mainly alpha and beta amylase) can convert those starches into sugars. But this only happens under the right conditions: the grain needs to be crushed, mixed with water, and held at a specific temperature range (roughly 148-162°F) for an extended period.

Once conversion is complete, we need to separate the sweet liquid (wort) from the spent grain. How you do this separation is where traditional and BIAB methods diverge.

Traditional Three-Vessel Brewing

The "traditional" all-grain setup uses three separate vessels:

1. Hot Liquor Tank (HLT): Holds and heats your brewing water (called "liquor" in brewing terminology)
2. Mash Tun: Where the grain steeps in water at mash temperature. Usually insulated and equipped with a false bottom or manifold for draining
3. Boil Kettle: Where you collect the wort and conduct your boil

How It Works

The traditional process goes like this:

1. Heat water in your HLT to strike temperature
2. Transfer water to mash tun, add grain, mix well
3. Mash for 60 minutes while the tun holds temperature
4. Vorlauf: Drain wort slowly and recirculate until it runs clear
5. Lauter: Drain the clear wort into your kettle
6. Sparge: Rinse the grain bed with additional hot water from the HLT to extract remaining sugars
7. Collect wort in kettle, proceed with boil

Advantages of Traditional Method

• Better efficiency: Sparging extracts more sugar from the grain, typically 70-80% efficiency vs. 60-70% for BIAB
• Temperature stability: Insulated mash tuns hold temperature without attention
• Clearer wort: The grain bed acts as a filter during lautering
• Easier to scale: Works well for large batches where lifting isn't practical
• Step mashing: Some systems allow easy temperature adjustments for complex mash schedules

Disadvantages of Traditional Method

• More equipment: Three vessels plus hardware adds cost and complexity
• More space: Harder to fit in a small kitchen
• Longer brew day: Sparging adds 30-60 minutes
• More cleanup: Three vessels to clean instead of one
• Higher initial investment: $200-500+ just for basic equipment

Brew In A Bag (BIAB)

BIAB simplifies all-grain brewing to its essence: one pot, one bag. The method originated in Australia in the early 2000s and has spread worldwide.

How It Works

1. Heat full volume of water in a single pot to strike temperature
2. Place grain bag in pot, add crushed grain
3. Mash for 60 minutes, stirring occasionally and adjusting heat as needed
4. Lift bag and let it drain (optionally squeeze to extract more wort)
5. Remove bag, proceed directly to boil in the same pot

That's it. No sparging, no transfer between vessels, no complex equipment.

Advantages of BIAB

• Simplicity: One vessel, one process, done
• Lower cost: Just need a pot, a bag, and basic tools
• Less space: Works in any kitchen
• Faster brew day: No sparging means 30-60 minutes saved
• Easier cleanup: One pot, one bag to wash
• Perfect for small batches: Scales down beautifully to 1-gallon
• Lower barrier to entry: Can start immediately with equipment you probably have

Disadvantages of BIAB

• Lower efficiency: Without sparging, you leave some sugar in the grain. Plan for 5-15% more grain to compensate
• Temperature control: A regular pot loses heat; you may need to apply periodic heat
• Physical effort: Lifting a wet grain bag gets heavy for larger batches (5+ gallons)
• Cloudier wort: No grain bed filtration means more proteins/particles in your boil

The Efficiency Question

The most common objection to BIAB is efficiency. If you're getting 65% efficiency instead of 75%, doesn't that mean you're wasting grain?

Let's do the math on a 1-gallon batch:

Method	Efficiency	Grain Needed	Grain Cost (~$1.50/lb)
Traditional (75%)	75%	~1.8 lbs	$2.70
BIAB (65%)	65%	~2.1 lbs	$3.15

The difference is about $0.45 per batch. For a 5-gallon batch, it might be $2-3 more. Meanwhile, the traditional setup costs hundreds more in equipment.

Yes, traditional methods are more efficient. But the practical difference in ingredient cost is small, and BIAB saves money everywhere else.

The "Squeeze the Bag" Debate

You'll hear conflicting advice about squeezing the grain bag to extract more wort. Some say it pulls tannins and astringency. Others say that's a myth.

The research suggests gentle squeezing is fine. Tannin extraction is primarily a function of pH and temperature, not pressure. If your mash pH is reasonable (5.2-5.6) and you're not sparging with scalding water, squeezing won't hurt your beer.

That said, don't go crazy. A gentle squeeze to get the free-flowing liquid is good. Wringing the bag like a wet towel probably goes too far.

When Traditional Makes Sense

Despite BIAB's advantages, traditional systems have their place:

• Large batches: If you're regularly brewing 10+ gallons, lifting isn't practical
• High-gravity beers: The efficiency difference matters more when you need a lot of sugar
• Style accuracy: Some traditional styles benefit from the clearer wort
• Dedicated brew space: If you have room for a permanent setup, why not use it?
• Personal preference: Some brewers just enjoy the traditional process

When BIAB Makes Sense

BIAB excels in many situations:

• Beginning all-grain brewing: Lower investment, simpler process
• Small batches: Perfect for 1-3 gallons
• Limited space: Kitchen/apartment brewing
• Limited time: Shorter brew days
• Experimentation: Easy to try new recipes without committing resources
• Most homebrewers, most of the time: It just works

Can You Make Good Beer With BIAB?

Absolutely. Award-winning beers have been made with BIAB. The method has no inherent quality ceiling — any style can be made well with either approach.

The slightly cloudier wort from BIAB typically clears during fermentation and cold conditioning anyway. Any efficiency loss is easily compensated by adding a bit more grain.

What matters for beer quality is sanitation, temperature control during fermentation, fresh ingredients, and sound technique. The method you use to make your wort is a distant consideration.

Our Recommendation

For someone just starting with all-grain brewing — especially at the 1-gallon scale we focus on — BIAB is the clear choice. It's how we designed all the recipes on this site.

Down the road, if you decide to scale up, brew frequently, or want more control, you can always add equipment. The skills you learn with BIAB transfer directly. Understanding mash temperatures, conversion, and wort production is the same regardless of method.

Start simple. Make beer. Enjoy the process. Equipment upgrades can always come later.