Thora

A new public hop from the USDA Agricultural Research Service and the Hop Quality Group, the first from their decade-long collaboration, per Crosby Hops. Named for the Old Norse word for thunder.

Dual purpose

Origin United States

Bred by USDA-ARS hop breeding program

One source

Bitterness: Moderate (8.7–8.7% alpha)
In the glass: 6 beers here · 1 fresh hop
Swap it for: Melba · compare them →

Brewing values

range on filetypicalbreeder or labmerchant

Alpha acid

8.7%

8.7

1 source

Crosby Hop Farm8.7–8.7

Beta acid

3.2–4.3% typical 3.8

3.2 4.3

1 source, spread of 1.1%

Crosby Hop Farm3.2–4.3

Alpha to beta runs about 2.3:1, which is what governs how fast the bitterness fades in storage.

In the glass · 6 beers from 4 breweries

Thora Fresh Hop Fiend-CLS Farms Stoup Brewing · fresh hop
Summer Classic Breakside Brewery
It’s a Metaphor Cloudburst Brewing
Thunder Road Cloudburst Brewing
Thora West Coast Pale pFriem Family Brewers
Please & Thank You IPA (Fall 2025) Stoup Brewing

What to swap it for

Melba 30

aroma — · oils — · chemistry 99 partial data
Styrian Cardinal 29

aroma — · oils — · chemistry 98 · shifts dual to aroma partial data
Boadicea 29

aroma — · oils — · chemistry 97 partial data
Barbe Rouge 29

aroma — · oils — · chemistry 97 · shifts dual to aroma partial data
Karma 29

aroma — · oils — · chemistry 97 partial data
Northern Brewer 29

aroma — · oils — · chemistry 95 partial data

Scored on aroma overlap, oil composition and acid chemistry, then nudged up where a brewer has vouched for the swap by hand. An axis we haven't measured earns nothing, so a hop known only by its acid numbers caps out around 30 — the score is how much evidence there is for the swap, not just how close the numbers happen to be. Anything under 50 is a different beer, not a substitution.

Pedigree

Parentage unrecorded.

Notes on this record

purpose defaulted to dual, unconfirmed -- Crosby Hops describes its intensity but not its role.

For brewers and data folks: this hop as JSON · the source file