I recently brewed an Imperial Red. It clocked in at around 1.072 on original gravity reading.

My malt bill looked something like this:
12 lbs 5.0 oz Pale Malt (2 Row) US (2.0 SRM)
11 lbs Marris Otter (2.0 SRM)
2 lbs 9.6 oz Caraamber (30.0 SRM)
1 lbs 15.1 oz Cara-Pils/Dextrine (2.0 SRM)
1 lbs 15.1 oz Munich Malt (9.0 SRM)
1 lbs 15.1 oz Wheat, Flaked (1.6 SRM)
1 lbs 11.8 oz Caramel/Crystal Malt - 60L (60.0 SRM)
11.2 oz Special B Malt (180.0 SRM)

Yeastex and Whirfloc at the recommended dosages for good measure.

I performed a 65 minute single mash. I mashed in at around 165 F and the mash rest occurred at around 155 F. I was able to extract nearly 5 gallons of wort. I batch sparged at 178 F, and the batch rest occurred for about 15 minutes.

The boil was 60 minutes with a very healthy hop schedule.

I copper coil chilled to about 78 F before pitching two vials of White Labs California Ale yeast. No starter. The first phase of fermentation occurred the way it usually does. There was a nice bubble in the airlock, with a solid couple inches of trub. 17 days have passed. I checked the gravity for the first time and the hydrometer measured 1.040.

This has me a bit concerned. I am still fairly novice to the all-grain game. I know but am not certain that big Crystal malts carry a lot of complex sugars that take the yeast extended periods of time to act on (Disachharides?). Did I mash too hot? Did I use too much Crystal? Why are the yeast responding so poorly to what would otherwise be considered a healthy brew? I am worried that the FG won't sink below 1.030 (this happened a month ago with a slightly different recipe). Would it be heinous to boil up some belgian candy and introduce it to the fermenting device to get the gravity low enough to bottle?

Thank you for all your advice.

3 Answers 3


Is this a 10 gallon batch?

The crystal malts are only around 10% of the grist, so I don't think you have a problem there. I would consider 78 F too warm for pitching WLP001, but I doubt that's your problem either.

My guess is that the fermentation has slowed down because you under pitched and presumably didn't oxygenate the wort. Each White Labs vial would have between 75 and 150 billion cells. According to Mr. Malty you closer to 500 which you can get from 2 vials in a 6 litre starter. Oxygenating the wort just before pitching the yeast helps the yeast replicate, and is good for a healthy fermentation.

My advice is to get another vial of WLP001, build up a good sized starter and pitch it while it's actively fermenting. Don't oxygenate the beer now, it will just promote staling.


I put this into the calculator at Brewer's Friend (approximately, what with 1lbs. 15.1oz anyway?) and got an OG of 1.092 and FG of 1.024.* So maybe you you should ask why you missed the OG.**

Marris Otter is not overflowing with enzymes like most 2-row is, so your mash is more sensitive to small mistakes. And your mash temp is on the upper edge for beta-amylase activity. If some of the mash was actually warmer (not stirred enough or thermometer needs calibration) then you could have made a very dextrinous, but not so fermentable, wort.

Does it taste sweet? Are you able to run a starch test on it?

Throw some yeast at it, as Tobias recommended. If it doesn't help much, then it's just an unfermentable wort. Great place for some brettanomyces!

*Using 75% efficiency, and 10 gallon batch. This calculator works off an assumed efficiency. Even though you can enter a mash temp, that entry does not affect the calculated gravity.
**Really, what's the batch size?

  • Sorry. I did forget to mention this was a 10 gallon batch size. I'm not totally opposed to the idea of a Brett infusion at this point. How much and what types would you suggest? I will definitely opt for another round of yeast with an oxygenated starter. I would've oxygenated before pitching but forgot to make a run to the hardware store and they were closed by the time i began wort chill. The information about Marris Otter makes too much sense, and is fantastic information going forward. Thanks again for all your help. Commented May 21, 2015 at 14:44
  • I've used Brett B a few times, makes a nice fruity flavor if conditions are right, or sometimes a horsey flavor (which I also like). Pitch size seems to be no so important; some say less pitch = more flavor. I wouldn't jump into that yet, it will take months to work.
    – Pepi
    Commented May 24, 2015 at 4:38

It is a bit late, but have you tried just moving the fermenter to a warmer environment?

If I get a "stuck ferment" my first step is to move the beer to a warmer area. The second step is to agitate the fermenter (and thereby the yeast) a bit by a bit of shaking or swirling. I do not open the fermenter!

Hope you got your FG.

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