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Ale yeast

US-05 / Chico

The clean American ale workhorse. The most-used yeast in craft brewing.

Also known as:Chico · California Ale · Wyeast 1056 · WLP001 · Imperial Flagship A07
Category
Ale yeast
Attenuation
73-80%
Flocculation
Medium-low
ABV Tolerance
11%

What it tastes like

If you've had an American IPA, pale ale, or amber ale brewed since 1980, you've tasted US-05 — or one of its identical siblings. Sierra Nevada Pale Ale popularized it. It produces remarkably clean, neutral fermentation that lets hops and malt express themselves without yeast character getting in the way. This is the default yeast for American craft, period.

cleanneutrallets hops/malt showsubtle citrus at warm temps

Best in these styles

Fermentation profile

Starts fast, finishes dry. Will produce slight peach/citrus esters above 70°F, but stays remarkably clean at recommended temps. Drops out slowly — many brewers cold-crash to clear.

Temp range
59-72°F (15-22°C)
Ideal temp
65-68°F
Esters
Minimal — clean, neutral profile
What to avoid
Pitching warm. US-05 stress at high temps produces fusel alcohols and acetaldehyde. Keep it under 68°F during active fermentation. Also: don't expect dramatic ester character — this is by design.

Available as

US-05 / Chico is sold under multiple supplier brand names — same or near-identical strain.

FormatSupplierProduct codeNotes
Dry yeast Fermentis US-05 11.5g
Dry yeast Lallemand BRY-97 11g
Slight difference in attenuation; some brewers prefer it
Liquid Wyeast 1056 100B cells
Liquid White Labs WLP001 100B cells
Liquid Imperial A07 Flagship 200B cells

Comparable strains

If you can't source this strain, these alternatives bring overlapping character or fermentation behavior.

Bry 97
See your supplier for details
Wlp001
See your supplier for details
Imperial Flagship
See your supplier for details

History

Isolated from a Sierra Nevada Pale Ale fermentation in the late 1970s and propagated through White Labs, Wyeast, and Fermentis. It's been the default yeast of American craft beer for over 40 years. Some sources claim it descends from the Ballantine Ale strain; the lineage is debated but the impact is not.

Related brewing guides

← Back to yeast strain guide