I’m going through my recipes to see when I used it. I brewed a Kellerbier in Nov '25 with S-23 fermenting at 49F, no diacetyl rest. I really enjoyed that beer and never picked up any odd or fruity flavors. When I use dry yeast I use two packets and sprinkle it directly on top of the wort. I know I’ve used S-23 at least one more time but can’t find my notes, but I’m pretty sure there were no negative outcomes from the yeast. Two data points for me, maybe not very useful, but certainly nothing bad. My go-to dry lager yeasts are Ferments S-189 and Lallemand Diamond and I use liquid in colder months when it’s safe to ship, so my use of S-23 will probably remain limited in the future.
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I brewed thousands of liters with S-23.
On the 1st batch, we use 140g for 60 liters. (That’s 4 packs of 11g for a 5 Gallon batch, but we buy 500g bricks) Later we repitch a good amount of it.
I really like the S-23 in our lagers. We ferment at 10° Celsius and do a Diacetyl rest at 16°.
I tried other lager yeasts (liquid and dry), but kept returning to S-23.
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maybe it has something to do with this - Identifying Lager vs Ale Strains
maybe this simply is what it is, pitch rate, temp control etc i think is better now than ever before. maybe storage and proper transport from manufacturer to LHBS/Online warehouse to home is better and people are getting the proper results from S-23 they did not in the past.
Note the above by TROHNER who uses about 44g per 5 gallons, S-23 was one of the early dry lager yeasts i was aware existed. I think the options I had were basically S-23, W34/70 and then random stuff like Mauri Lager(?) and I never recall getting explicit instructions about adding more than one packet.
Again, maybe it got a bad reputation from it throwing a lot of odd flavours due to multiple stressors potentially occuring in the earlier days of homebrewing and that reputation stuck. Whereas say W34/70 was simply more stress resistant, so people would end up with still okay beers under poor conditions and not complain about it online.
and its frohberg despite past associations of it with saaz type Saaz-type vs Frohberg-type lager yeast strains
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I use S23 a lot. I primarily brew lagers and find yeast selection and health are essential to get the flavour profile I want. S23 throws the perfect fruity flavours in Bohemian Lagers which I usually use a double decoction mash. I ferment s23 at around 8 or 9 degrees for 21 days and do a rest at 15 or 16 before aging it for a few months close to 0. I have never had an issue with it or complaints about the beer.
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I really like it, but i’d never call it fruity. An ester, sure, but never fruity to my taste.
Had an early sample of my just kegged 3% amber lager with it, very happy with it ( as usual )
The term ‘fruity’ and its sister ‘ester’ are unhelpfully broad IMO. According to ChatGPT; Fermentis’s measured ester concentrations for S-23 aren’t dramatically higher than W-34/70:
| Ester character | S-23 | W-34/70 | Likely impression |
|---|---|---|---|
| Ethyl hexanoate | 0.8 | 0.8 | red apple |
| Ethyl acetate | 1.3 | 1.4 | general fruity ester |
| Isoamyl acetate | 1.9 | 1.9 | banana/ripe fruit |
What fruit flavor are those who detect it perceiving?
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FWIW, one of my S23 beers was so weird I sent some to John Palmer. He said it tasted like Bartles and Jaymes passion fruit wine cooler.
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Tropical fruit
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My perception of the fruitiness was Juicy Fruit gum. 34/70 can kick out red apple, but can be controlled with pressure/temperature or both. I tried the same method with S23 and it just got weirder, so I gave up on the yeast. To me, 34/70, S189 and Diamond are superior dry yeasts and it’s still enough variety that I don’t need more choices.
That being said, some people swear by S23. I dunno.
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Re brewed this one today, really enjoying it. 3% amber lager for sensible summer drinking. Today’s version should be under 3%.
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First anecdotal data point: my S-23 fermented Schwarzbier took 1st out of 6 beers at our monthly club challenge last night. I specifically asked one of our most experienced judges if he detected any fruit. He did not.
Interestingly, there was a Premium Czech Lager there also fermented with S-23. I didn’t detect any weird fruit flavors in it either though it came in 4th behind a Michelob clone and an Oktoberfest. My S-189 fermented Märzen came in 5th.
I cannot explain why some S-23 fermented beers have the weird flavors and others don’t.
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The re brewed version of my amber lager above is cooling in the fridge as we speak. Haven’t finished the first batch above, but can’t be too far away. Trying to be good, beer drinking wise, as i have an Aqua bike event in 6 weeks, but i am regularly “sampling” haha
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Years ago on the B&V, I concurred with Denny on the passion fruit flavor. I deduced that my issues with was from fermenting cold (below 50°F).
Over the last 20 years, I started to see that other homebrewers are having some success with it. That’s fine and dandy. but by that time other dry lager yeasts had been released, that I really like, so I found no incentive to try S-23 again.
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Interesting point about temp. I’ve only used S-23 at 14-15c, and really like it. About to keg another batch today.
Second anecdotal data point: the Schwarzbier took 2nd place at its table in the 2026 Fugetaboutit homebrew competition. No mention of any odd fruit flavors by either judge.
as far as temp: I pitched at 55°F, raised to 57°F at 50%, raised it to 59°F at 75%, and raised it to 61°F at 90%. I held it there for a few days to metabolize any byproducts (D rest).
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