WLP004 Irish Ale Yeast

This is the yeast from one of the oldest stout producing breweries in the world. It produces a slight hint of diacetyl, balanced by a light fruitiness and slight dry crispness. Great for Irish ales, stouts, porters, browns, reds and a very interesting pale ale.

Jump To: Reviews | FAQs>
Play Audio Description of WLP004 Irish Ale Yeast »

Chris White, president of White Labs, discusses the company's strains.

Style Performance Listing

A listing of how this style ranks amongst different brew styles, on a scale from 0 to 4.

Style Rating Style Rating
American Style Cream Ale2American Style Wheat Ale2
Fruit Beer2Herbs & Spice Beer2
Specialty Beers2Specialty Honey Ales2
Smoke Flavored Beer2Golden Ale Canadian Style Ale2
German Style Kolsch2Classic English Style Pale Ale4
English Style India Pale Ale4American Style Pale Ale2
American Style India Pale Ale2American Style Amber2
English Style Bitter4English Style ESB4
Scottish Style Ale2Irish Style Red Ale4
English Style Brown Ale2American Style Brown Ale2
German Style Brown and Dusseldorf Altbier1Robust Porter4
Brown Porter2Classic Irish Style Dry Stout4
Foreign Style Stout2Sweet Stout4
Oatmeal Stout4English Old Ale English & American Strong Ale4
Barley Wine Strong Ale2Strong Scotch Ale2
Imperial Stout2Imperial IPA2


Feedback and experiences from previous customers. Want to leave a review of your own?

Irish Red Ale

By: James Mathieu | Date: Feb., 2nd 2016 | Beer(s) Brewed: Irish Red ale

Made a 1.5L starter from a recycled batch of this Irish ale yeast I harvested from a porter I brewed in December. Brewed a traditional Irish Red with an OG of 1.052, and and pitched around 70 degrees. Left outside on a cool San Diego night, and the next morning it was happily fermenting at around 62 degrees. After one more night outside, still strongly fermenting at 58 degrees. Brought inside and now maintaining temp of 64 degrees. Looking forward to seeing how this one turns out!


By: Tom J | Date: Jan., 19th 2016 | Beer(s) Brewed: Stout

Did a 1L starter of WLP004 (PurePitch) , put it on a stir plate for 48 hours. Pitched into a 1.049 Stout @ 70 degrees. 24 hours later, I have a monster on my hands. Probably over pitched, but whatever. Can't wait to taste it.

Bold taste

By: Dave Dr | Date: Jan., 4th 2015 | Beer(s) Brewed: irish brown, stout, pale ale

I don’t really like Irish and English yeasts as there are so many other styles I prefer but thought I’d give this one a try. I made a 2 quart starter with 1 cup light malt extract and pitched in 21 gallons of three different beers, as I do with all Whitelabs yeasts. I made: (1) Brown Ale, (2) blueberry stout (mashed 4 pints of just picked blueberries and added to wort just before cooling), and (3) Pale ale. The yeast performed as expected. The only thing I found unusual was in my secondary, a thin layer of white film collected on the surface. I scraped it off before bottling and all was well. I don’t think I’ll use this one again as the taste was a little bolder than I like. The best analogy I can use is that it was like a Maduro cigar – bold and strong. It had great head retention and color, starting gravities were 1.074-1.080 and ended at 1.008, but I like the German and IPA yeasts better. However, might be worth a try if looking for a heavy, bold, obviously Irish taste.

Great for a wide variety of ales.

By: Joebob Jacobs | Date: Oct., 31st 2014 | Beer(s) Brewed: Pumpkin, Brown, Robust Porter

I have used WLP004 for 8 years and am always amazed at its versatility. Most recently it has won praise for my Punkin Ale, a 7.4% Sweet Potato Brown Ale and is currently fermenting my trusty old Robust Porter. Ferments well even at 64F, slow and steady.

Fast and violent fermentation

By: Deebee | Date: Jun., 26th 2014 | Beer(s) Brewed: ESB

Made an esb type a while ago in a 2 litre starter. fermentation was of already after about an hour in the wort. next day saw the fv lid split and a yeast monster spray the walls. Took about 2 days to settle down. finished fast and flocked nicely. Am wondering about doing a russian imperial stout with this for an og of 1.099(abv around 10.5) but am unsure as to whether it would handle it. Will be a 10 l brew and i have the entire yeast cake saved. thoughts?

Great for an Irish Red

By: Peter Matthews | Date: Sep., 9th 2013 | Beer(s) Brewed: Irish Red

I recently made a lovely Irish Red with this and the results are fantastic. I used two vials in a 2L starter (but could probably get away with just one 1L next time) and started a 5 gallon batch at 1.040. Primary fermentation finished after eight days at 1.012 which was slightly above expected minimum attenuation. I thought the beer may be a little sweet because of this but the yeast gives a really dry taste even at a relatively high final gravity. This gave me a lovely dry, almost stout like beer at around 4%ABV. I have made an extra strong Guinness style beer with this yeast before ending up at 8% ABV so it can handle the higher alcohol beers well.

I believe the reason I didn't hit my target final gravity was because I allowed the temp to drop dramatically one night so would recommend even some basic temp control such as a heater pad at night if your temperature goes below 10oC. The yeast bubbled away happily at temps between 15oC - 23oC which is larger than the recommended range.

English Mild

By: Nathan | Date: Jun., 2nd 2013 | Beer(s) Brewed: Mild

Wondering How this strain works for English Milds... I will let you know Bjcp 11A.

Wow! Great yeast - started in 12 hours at 70 degrees

By: blkcld5150 | Date: Dec., 1st 2012 | Beer(s) Brewed: St. Peter's Old Style Porter clone

Wow! Great yeast - started in 12 hours at 70 degrees. The best beer I have brewed! Amazing clarity and clean taste. Really brought out all the roasted malt flavor in this beer. Just brewed a milk stout using this yeast and am hoping for same result!

I used this strain for the first time

By: Brulosopher | Date: Nov., 28th 2012 | Beer(s) Brewed: Dry Stout

I used this strain for the first time, brewing a rather traditional Irish Dry Stout for an upcoming club competition. It fermented fast at about 66F and produced a very clean tasting Stout with a very slight acidic tartness (?), which resembles what I get when I drink Guinness. I also brewed an English Mild using this yeast... it's good, just not very English. I'm calling it an Oirish Mild, as it too has that slight acidity and crisp dryness.

... it was going to town the next morning

By: Steve Ruch | Date: Nov., 19th 2012 | Beer(s) Brewed: Stout

I pitched the vial into a three gallon batch of stout with an O G of 1.061. I had signs of fermentation in four hours and it was going to town the next morning. After three weeks I racked to secondary and the gravity was 1.015 and tasted real good. I will use this yeast again

...well balanced...

By: Aaron | Date: Nov., 19th 2012 | Beer(s) Brewed: Stout

This is my house strain for stouts and some ales. Flavor profile is amazing, I've regularly got this yeast to 1.004 for the dry stouts. Also made an Imperial Porter with it as well. It keeps the hop profile in the background but still is well balanced.

This yeast produced a very flavorful/character

By: Dave Malone | Date: Jul., 5th 2012 | Beer(s) Brewed: Irish Red Ale, Old Ale

This yeast produced a very flavorful/character rich beer. It was quite, fruity, but I fermented at   the top of the temperature range. I didn't get any phenolics or other unwanted yeast   characteristics. It seems to accentuate caramel/bready flavors, but those were the flavors I was   going for. It would be interesting to see how an IPA or pale Ale would turn out with this strain.

... gotta drink ...

By: McSwiggin | Date: Oct., 15th 2011 | Beer(s) Brewed: Blonde Ale

Our club purchased the wlp004 Irish ale yeast to make an Irish dry stout. The same day we were also making a blonde ale with wlp005 British ale yeast. When it came time to pitch we mixed up the yeast (gotta drink beer to make beer). The result was a great English stout and an incredible blonde ale we dubbed Durty Nellie. It's a crowd favorite at parties and recently won third at the Orange County (CA) fair. I would recommend this yeast.

... takes off quickly ...

By: Steve | Date: Mar., 9th 2011 | Beer(s) Brewed: APA, Porter, Stout and Imperial Stout

This is an outstanding Yeast for Porters and Stouts of all types and works very well for American Pale Ales too. Leaves a very clean and malty tasting beer and balances the hops nicely. I have used this product on at least 6 different Porters and Stouts and an APA or two and have even washed and reused the yeast up to 3 times or just dumped a new batch on top of the old cake with no signs of problems. The yeast takes off quite quickly normally in 10 to 12 hours or less and if dumping on an old cake only about 2 to 4 hours. I have used other White Labs yeast as well as other brands and as far as I'm concerned White Labs products are the best and first pick for my brewing.

... off to the races

By: surferdrew | Date: Jan., 10th 2011 | Beer(s) Brewed: Strong Scotch Ale

WOW...pitched a 1.5L starter into 5 gallons of wort + oxygen and it was off to the races! Wanted to experiment with lower fermentation temperatures and at 58 degrees (ambient) it attenuated fully in only 72 hours (1.070 to 1.018).

Incredible flavor

By: Anonymous | Date: Oct., 23rd 2010 | Beer(s) Brewed: Irish Stout

First time I use liquid yeast and I didn't think it would need so much stirring (flocculation) and be so shy to show signs of activity (took 24 hours). Incredible flavor. I hope a very good beer. This yeast seems to be a really good way to improve my homebrewing.

Just made a brown ale ...

By: Anonymous | Date: Oct., 17th 2010 | Beer(s) Brewed: IPA, Brown

Won an Arrogant Bastard clone competition amongst 10 of our members using this year. Very clear in the bottle and keg. Just made a brown ale using a repitch that had been sitting in the fridge for 5 months. Restarted in 1 liter and a day later going strong. Hearty yeast no doubt!

Primary fermentation was done quickly ...

By: WallyG3 | Date: May., 20th 2010 | Beer(s) Brewed: Dry Irish Stout

The second time I used this yeast, I fermented at 66F. Primary fermentation was done quickly and I kegged it after only 8 days. The result was noticeable diacetyl. Next time, I will go 68F and let it sit for 2 weeks to clean that diacetyl up.

The bottles cleared nice after 1 week

By: Jeremy S, Des Moines, IA | Date: Feb., 26th 2010 | Beer(s) Brewed: Oatmeal Stout

Very nice for stouts, my oat stout was on the lighter side by design, has a nice smooth character after only 3 weeks, 2 in primary and 1 in bottles so far. I was fermenting in a bucket, fully attenuated, but couldn't see it clear, I WOULD DEFINITELY LEAVE IN PRIMARY 3 WEEKS NEXT TIME. The bottles cleared nice after 1 week and carbonated quickly because of all the yeast still in suspension. I don't think it will keep for longer aging because of how much yeast settled out and is now in the bottles. It will be gone in a month anyway. I fermented at 68 to 70 degrees and didn't need much head space, no more then 2 inches of krausen in my bucket, flocculated pretty solid even though the beer didn't clear for 3 weeks. That 1/16 of an inch of yeast in my bottles is stuck pretty well to bottom, no worries pouring.

I really like the clean taste

By: Kevin | Date: Jul., 16th 2009 | Beer(s) Brewed: IPA, Stout, Brown Ales, Red Ales, ...

The love story began with a Stout, then an IPA made it become my "house yeast". I'm now using it for any red or brown ales recipes. I really like the clean taste, and the light fruity after-taste. I've also noticed that an ounce or a bit less of torrefied malt (carafa 2) in amber, red or dark ales produces a really nice and complex aftertaste that I can't get tired of. She is a winner!

... definitely using this again!

By: opticman | Date: Apr., 27th 2009 | Beer(s) Brewed: Sweet Stout

First Stout I have brewed and this is an amazing yeast! With the 1 Liter starter I made, lag time was only 3 hours! This yeast flocculated very well, and the finished product is far superior than any commercial Stout I have had. I am very impressed with WLP004 Irish Ale yeast, definitely using this again!

This is gonna be tasty!

By: jjames17407 | Date: Jul., 27th 2008 | Beer(s) Brewed: Irish Red, Irish Stout

I've used dozens of yeast strains that White Labs produces, but the WLP004 Irish Ale yeast is fastly becoming my choice for all Ale and Stout homebrewing! I've never seen a strain of yeast take off as quickly as WLP004, my latest Irish Red was pitched at 2 p.m. on brew day and was already blowing off at 7 a.m. the next morning! This is gonna be tasty!

The beer took a 1st place

By: Michael A. | Date: May., 5th 2008 | Beer(s) Brewed: Strong Scotch Ale /Wee Heavy

This yeast produced a malty, full bodied ale. The beer ended up around 10-11% ABV with some (not much) residual sweetness. The finished beer took a 1st place ribbon in a hombrew contest.

... smells delicious while fermenting

By: Jesse Cronce | Date: Feb., 25th 2008 | Beer(s) Brewed: Oatmeal Stout, Old Ale

Irish ale yeast imparts a delicious fruity character to beer, which works very well with stouts, porters, and my most recent beer an Old Ale. The fruitiness pulls the residual sweetness of brown sugar together with a hoppy spicy bite for a very balanced brew. Also, IAY smells delicious while fermenting. No elephant farts!

... the yeast was robust

By: TJ Vitolo | Date: Sep., 27th 2007 | Beer(s) Brewed: Irish Red

I used this yeast to make an Irish Red as part of a wedding gift. Having gone out of my realm of brewing wheats and in the midst of the summer, I was not sure I could keep the temperature low and I was right. Although the temperature slightly exceeded (+2 or 3 degrees) the recommended range, the yeast was robust and yielded a beer that was a hit. I gave the beer sufficient time to age and work out diacetyl and in the end it the beer was true to style, and true to the yeast description having a hint of diacetyl, light fruitiness and a dry finish even though it had a malty profile.

Great Irish style stout

By: Anonymous | Date: Jul., 13th 2007 | Beer(s) Brewed: Oatmeal stouts

Great yeast to create nice dry stout. For years I have tried other dry and liquid yeasts, but this one definitely will give you a great Irish style stout. Works great in Imperial and Oatmeal Stouts as well. Nice yeast!

... Every beer turned out great

By: David Dameron | Date: May., 31st 2007 | Beer(s) Brewed: All Grain. All Styles.

I used this yeast for the first time in an all-grain Irish Stout kit I purchased last year. I was so impressed with the results that I tried it in one of my home made Pale Ale recipes. To make a long story short, I brewed about 20 batches of beer last year. Everything from Pale Ale to Red to Nut Brown to Porter to Stout. I used this yeast in every beer and every beer turned out great. This is definately a great yeast for all-grain brewing.

... Produced an excellent stout

By: Matthew Wood | Date: May., 21st 2007 | Beer(s) Brewed: porter, stout

This yeast produced an excellent stout as well as the best porter I have ever tasted. It produced a very complex and pleasing flavor in each, and mellowed well and noticeably week to week even after 6 months in the bottle.

... Hint of cherry

By: Gointomexico | Date: Nov., 18th 2006 | Beer(s) Brewed: Export tout, dry stout, brown ale

Some malt flavor, hint of cherry. Smoke flavor goes away in time.

Frequently Asked Questions



FlocculationMedium to High

Optimum Ferment Temp.65-68°F (18-20°C)

Alcohol ToleranceMedium-High

MiniFerment Data ?

As-is Diacetyl21.87ppb

Total Diacetyl87.81ppb

As-is 2,3-PentanedioneN/A

Total 2,3-Pentanedione13.1ppb



Ethyl Acetate25.53ppm

Isoamyl Acetate0.615


Isoamyl Alcohol186.27ppm


Final Gravity: 68 °F Hours to get to 50 percent attenuation: N/A