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We are brewing a Saison-style, all-grain beer. We had a multi-stage, multi-temperature mash process requiring us to get the mash to a set temp then hold it for a period then increase the heat and repeat. This process went smoothly.

We completed the sparge and subsequently the boil, and all went to plan.

We cooled, pitched the yeast and commenced the primary (aerobic) fermentation for one week.

We then transferred to our secondary (anaerobic) fermentation, and this is where things started to awry. We had an OG of 1063 and we're targeting an FG of 1015-ish. We've had a very active secondary fermentation, yet after almost three weeks the gravity is still only 1040 and has been holding steady for a week at this level, whilst still very active in the fermenter.

Doubt and worry is creeping in. We don't want to bottle whilst the gravity is still this high, but we don't quite know what's wrong or what to do next.

Any suggestions / explanations / recommendations for next steps would be very gratefully received.

Thanks!

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  • It would help to know what yeast you used (some saison yeasts are notorious for stalling!) and what temperature you're fermenting at. And, FYI, primary fermentation is anaerobic except for the first 12 - 24 hours when the yeast is metabolizing the oxygen dissolved in the wort.
    – FishesCycle
    Commented Dec 12, 2014 at 4:17
  • First, ditto to what Tobias said. Second, one week of 'very active' should get 1.040 to 1.00x. Is there foam on the beer? Bubbles coming at least a few times per minute?
    – Pepi
    Commented Dec 12, 2014 at 8:51
  • Thanks Tobias, in terms of yeast, we used a liquid yeast: WyYeast Belgian Saison 3724 We are fermenting at room temperature, which is reasonably warm at the moment, probably 18-19 degrees Centigrade. The thing is it hasn't stalled as such, still bubbling through the airlock and froth on top of the beer. Sorry, I should have also added to the OG was 1073, and is down to 1040, is still very active, but the gravity isn't dropping any further, and that's been holding steady for well over a week, almost two.
    – LindsayWelsh
    Commented Dec 13, 2014 at 0:12
  • According to the wyeast website: "This strain is notorious for a rapid and vigorous start to fermentation, only to stick around 1.035 S.G. Fermentation will finish, given time and warm temperatures. Warm fermentation temperatures, at least 90°F (32°C), or the use of a secondary strain can accelerate attenuation." So gentle warming seems warranted.
    – Pepi
    Commented Dec 13, 2014 at 3:31
  • Or if you want to add in another strain, I can tell that 3711 works great from 15-30C, but maybe somebody else can comment whther the flavors would conflict, or whether a neutral stain should be used. And I'm still wondering how you guage "very active", because the hydrometer is saying "very not active".
    – Pepi
    Commented Dec 13, 2014 at 3:33

2 Answers 2

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As noted in the comments, WYeast 3724 is well known for stalling/slowing down at around 1.035. I've used this yeast in the past, and it will eventually achieve over 80% apparent attenuation. I used a brew belt to heat the beer, and wrapped the carboy in blankets to insulate it. This brought the temperature up to the mid 80's F. It took a few weeks to finish fermenting, even at that temperature.

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  • Tobias, thank you too for your helpful response and suggestions. We put the brew onto our heating pad and brought the temperature up to the mid 20s C. Overnight we dropped from 1040 to 1036 (still above the 1035 figure you and Pepi warned me of). Will be keeping a close eye on it over the next couple of days and hopefully we'll see the gravity reading dropping to the required levels. Thanks again for your help on this.
    – Lindsay Welsh
    Commented Dec 14, 2014 at 21:01
  • Sitting with one right now in the fermenter at 90F (32.2C). Went from 1.035 to 1.022 over 2 days. You can either give it time and temp, or drop S05 in it.
    – Wyrmwood
    Commented Dec 16, 2014 at 22:04
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Supposedly WY3724/WLP565 (aka Dupont) is a wine yeast that evolved over time to work in a brewery application (Dupont's brewery). This would explain why it can work at higher temps than most brewer's yeasts without producing fusel alcohols and excessive phenols/esters.

With respect to it stalling, another characteristic of wine yeasts is that many of them do not work effectively under pressure. Homebrewing setups, along with commercial brewhouses are set up to have the ferment pressurized (either from gas in the headspace in the case of homebrewing or from forced pressurization in some commercial brewhouses).

The solution that I have heard to this (but not yet tried) is to use a piece of foil taped over the airlock bung instead of an airlock. This will let out a lot more gas and not pressurize the fermentation. I am dying to make a saison now with Dupont, because while there are other yeasts that can make a good saison (including 3711 which I have used and like), Dupont consistently will make a GREAT saison (if treated right!).

Finally as a general rule, it is not necessary (or recommended by most modern homebrewers) to rack off the yeast until your beer has reached the desired STABLE final gravity, or preferably after it has.

It may be a little late to try it on this brew, but I would think the combination of warming, rousing, and depressurizing might get it moving again. If that doesn't work, grow up a slug of brettanomyces and let that finish it off, and try this on the next beer. Good luck.

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  • We talk about 3724 in our book "Experimental Homebrewing". My co author, Drew Beechum, is pretty much the master of saison and has used 3724 a lot. Besides the temp increase, the other thing to note is that yeast hates any back pressure at all, as noted above. Drew recommends using an open fermentation with it.
    – Denny Conn
    Commented Dec 16, 2014 at 16:23

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