What are the most citrusy hops?

Here is a pretty useful chart of different types of hops and the flavors they tend to impart on beer.

Hops - Bitterness, Flavors & Aromas.

Things change depending on year and growing location, as well as hop style, but this is a good general idea.

I love sorachi ace Specially in saison Very lemony. Very aromatic

+1 on Simcoes. A buddy of mine did a Pliny clone with an 12oz hop bomb of simcoes in the bright tank (15 gallon batch) and the hop aroma was beautifully orange-y.

Why not take a simple grain bill (90% base, 10% caramel), clean yeast (WL California Ale) and split it into 2 or three batches, each with a single varietal and the same schedule (eg 60, 30, 10, 5, dry). I did a great split batch single-hop series like this with citras and amarillos...got a great feel for both of them and wound up with 4 cases of great APAs!

You can even do this by mashing to a higher-than-desired gravity, then diluting with water to a 6 gallon pre-boil volume (though hop additions/hitting the right IBU's can get tricky in this scenario, make sure you know how to finagle your brewing software).

I personally try to maximize my time-spent-brewing:beer-made ratio...great way to do this.

In the American hops like those listed above (Cascade, Amarillo, Columbus, Citra, etc.) the citrus is mostly grapefruit (plus tropical fruits which aren't necessarily citrus).

Many people think the Japanese Sorachi Ace hop has a distinctly lemon aroma. I recently made a saison with it and it worked well with the esters produced by the yeast. Brooklyn Brewery also does a saison with heavy Sorachi Ace.

Amarillo, super galena and simcoe are the new varieties

Saaz hops is great for citrus. Many homebrewers never brew with Saaz... not sure why. Perhaps because it is traditionally a lager hop, or because it is slightly more expensive.

Bitter with Magnum, flavor/aroma addition with Saaz. I just brewed a 20L batch of Blonde Ale using a base of Pils malt, 1 lb rye, 1 lb corn sugar, Magnum bittering, Saaz for 30 mins. It is AWESOME... well received by craft beer drinking friends and the "Coors Light" people we all know.

I like Citra, Amarillo and Cascade for citrusy aromas.

I recently brewed a "Belgian" IPA where I used a combination of US Saaz, US Fuggles, and Mt. Hood, which managed to create a very nice citrusy flavor (Orange juice, actually). So don't forget that combinations of hops can produce new, unexpected flavors.

Citra is more tropical fruit than citrusy. It's really reminiscent of passion fruit. To me, Cascade is grapefruity, Amarillo and Summit are tangerine, Simcoe and to a lesser extent Centennial are lemony.

Centennial and, to a lesser extent, Cascade are the classic American "Citrus" hops. Dry hopping with Centennial will give you a nice grapefruit hop punch.

Very much like the results from Willamette (along with Cascade).

I have used Amarillo in an IPA before and when it came to bottling my wife said, the whole appartment smelled like grapefruit.

Per its name, Citra is also a good citrus-y variety. If you want to know what it adds, compare a Sierra Nevada pale ale (Cascade) to a Sierra Nevada Torpedo IPA (dry-hopped with Citra).

Cascade hops have a grapefruit aroma, and Amarillo, orange. Those are the stronngest citrussy hops I know of. I'd imagine you get most of the citrus flavour & aroma out of large amounts of late-boil, finishing, and dry hops.