Okay, I am making a strong (imperial-ish) red ale. My original gravity was 1.081. I intended to bring it to a final point at most of 1.020, or if I can even lower.

I was using 2 packs of WLP004 (Irish Ale Yeast). According to reviews it is possible to reach 8-8.5% of ABV with it. After 5 days fermenting process stopped and for last 5 days there was no activity. The gravity stopped at 1.030 and the ale a little bit too sweet.

The temperature of the carboy was within 64F-68F depending on time of the day. I am considering adding more yeast and keeping a temperature at 68F-69F (by using a heating belt at night).

Should I add WLP004 or can I use different one and combine them with WLP001 or WLP07? How much should I add? What are my other choices?

I'm kinda of trying to finish the bath in 2 weeks and condition in bottles for another 3 weeks and serve it by the first weekend in April...

Thank you for your help.

Thank you, everybody. I found an answer. Apparently, the rest of the sugars in my beer are not fermentable. I tried to run the recipe through the recipe calculator, and it says that with WLP004 the final gravity would be 1.029. If I used WLP007 it would get to 1.026.

With IBU of 86 and 1 week of dry hopping with 1oz of Simcoe, it is not bad. Not quite what I was hopping to get, but still good (I'll just call it a know-how).

I will be more accurate next time.

PS. I don't have enough space for full grain, thus I'm doing extract beer. With less control over my wort, it is little bit tricky.

  • There are a series of possible reasons for stuck fermentation and depending on the reason, the answer would vary. How do you cool your wort? How long does it take? How do you aerate? Did you make a starter? How did you aerate the starter? Also, how did you mash, is it possible you had to much alpha-amylyse?
    – markus
    Mar 2, 2014 at 11:54
  • You created more questions then answers... Made me think... thank you. No sarcasm, I really mean it. So, it was an extract beer with 6 gallons of boil size and 12lbs of LME. I never had any issues when I was using WLP001, WLP007 or WLP099. It took me about 30 mins to cool my wort and I used spiral wort chiller with a garden hose attached to it. I did aeration by shaking a carboy. I didn't do a starter (just transfered yeast to a carboy...
    – Trigger
    Mar 2, 2014 at 21:21
  • I just fixed a beer that was stuck at the dreaded 1.020 mark with some Amylase enzyme, from the homebrew shop.
    – GHP
    Mar 3, 2014 at 14:53
  • @markus-tharkun How do you get too much alpha-amylase?
    – brewchez
    Mar 3, 2014 at 17:37
  • @brewchez it's a question of proportion. If you create too much unfermentable sugar either by too high mash temperature (single step) or too long alpha-amylase phase (multi-step) you'll end up with a sweeter beer than you wanted. Also the food for the yeast finishes early, which is why I mentioned it in my questions.
    – markus
    Mar 3, 2014 at 18:41

2 Answers 2


At this point you don't know if the fermentation is stuck or finished. Despite the yeast attenuation rating, it's the fermentability of the wort that determines attenuation. Alcohol tolerance is not the problem. More yeast might help or it might not. Before you do anything you should try a fast ferment test to determine if there are any more fermentable sugars in the wort. http://braukaiser.com/wiki/index.php?title=Fast_Ferment_Test If the test shows you still have fermentable sugars, go ahead and add more yeast. If not, the beer is done and ready for packaging.


The fast ferment is a good idea. What temp did you mash at?

Ending at 1.030 is pretty high. You can throw in some champagne yeast and it won't change the character much, if at all. You can also throw in white labs 090 or 099, be careful of the 099 it can ferment very low.

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