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Attenuation of S04

I brewed NB’s Dry Irish Stout extract using S04 for the first time. Fermentation began at 61°F 6 hours after pitching. Evening of the second day krausen was bubbling through the air lock at 62°. Following morning no krausen through air lock at 63°. Evening of the third day the beer temperature dropped 2°. I began to slowly raise the temperature to 68°. Held temperature at 68° to today.

The beer has been in the fermentor now for 23 days. On day 13 the SG was 1.014. SG is holding at 1.014. No CO2 present in the sample. Taste of the SG sample is good. Very full body. Should I have a lower SG with this yeast based on your experiences with it? OG was 1.042.

Previously used WY 1084 for this beer. This yeast would finish the same recipe at 1.008 to 1.009.

Pretty much where mine would finish.

I just brewed that as well and matched your gravity readings.

I haven’t used S-04 in years. Is it one of the weird super-flocculating English yeasts? It’s supposed to be the same as WLP007 which attenuates close to 80%. In any case, I would encourage you to swirl the fermenter hard several times per day for a few days to get the yeast roused up into suspension and hopefully knock a couple more points off, as that FG does seem a bit high.

Good luck.

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Plan to do a forced ferment this morning instead of risking another fermentation finishing in the bottles.

S-04 is a beast. Quick start and finish. Attenuation is lower which allows more body which is one of the reasons why I like it. It does drop out fast though. I doubt it’ll lead to over-carbonated bottles with this beer and yeast. I tend to go lower on my volumes of CO2 with the dark beers anyway. I’ve used it for a couple of rye porters. FG was 1.019 and 1.020. I also used it on a BVIP. FG was 1.021. Working on a brown ale right now and used S-04. Bubbled aggressively for 3 days and pretty much stopped dead. I’ll get an SG reading next week. If you want a drier Dry Irish Stout, I’d go with US-05. I don’t think you’re going to get much drier than 1.014 with S-04.

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Good to hear. Maybe I’m okay. Went ahead with a forced ferment with bread yeast at 95°F. (Not really a forced ferment. More just checking for fermentable sugars.) Roused the yeast also along with beginning to raise the temperature of the beer to 72°F.

Forced ferment indicates the FG could go as low as 1.013. Probably be bottling in a couple of days.

Bottled the stout this morning. FG 1.009 after rousing the yeast and raising the temperature to 72°F. Thirty-two days in the primary.

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Good you waited

I have to share my recent experience with a brown ale and S-04. FG was 1.009. I had mashed it at 154 degrees F. I was hoping for more body and sweetness, but it tasted very drinkable at bottling. I went through my notes more thoroughly, and I did brew an Irish Red Ale last year fermented with S-04 that had an FG of 1.005. So I stand corrected. I think the FG truly depends on ultimate fermentability of the wort and not so much the yeast. These were lower OG beers compared to the Porters I had previously posted about on this thread. OG could possibly play a role as well.

I would suspect that the unfermentables in some malts… Browns don’t bring as much to the party… Thusly, leaving flavor compounds… Sneezles61

So, not to necro an old thread, but I just kegged Alpha Leonis from our hosts which I used US-04 on. I haven’t used it in several years. My mill was acting up so I missed my OG (I think it may be time to move on from my Captain Crush because it’s becoming a pain to use) and I left it in primary for 4 weeks due to life. :stuck_out_tongue_winking_eye: When I transferred it yesterday, I was baffled by my 1.028 FG. I haven’t had a beer finish that high since before I started brewing AG. Actually, it was the Imperial stout extract kit from our hosts and that one actually finished out at 1.036 and I also used US-04 on that. So now instead of a 6.5% tropical stout, I’ve got a 4.5% Session stout. :joy: Hydrometer sample was delicious. For reference, US-05 typically finishes out for me around 1.012 on the nose almost every time.


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