Stuck fermentations with good aeration and pitching

[ctdenney]

This is a problem I have with almost every beer I brew: extract or all grain, big beer or little, stater or not, they almost ALL finish high. Usually above 1.035.

I know that the usual causes of this are underpitching and poor aeration, and those were my first thoughts. But it has happened on big beers that I made a starter for and beers with an OG of 1.045. As for aeration, I have started swirling the chilled wort in the carboy for a full five minutes before pitching and putting on the fermentation lock, but it hasn't caused any improvement compared to when I used to only swirl for one minute. From what I have read, that should have been adequate aeration so I am going to try adding yeast nutrient for my next batch, but I don't expect it will work.

I have wondered if it might be the temperature since I don't have a way of controlling it with my current gear, but I leave my carboys inside where the temp is pretty consistent and every time I check the fermometers on the side of the carboys, it is always right around 65 degrees.

If if was one batch, I would get over it and move on, but literally every one of the last 6 brews I have done has ended higher than it should have. In addition to the yeast nutrient I am going to try to aerate better by pouring from a bucket through a funnel into the carboy (instead of going straight into the carboy from my counterflow chiller like I do now), but I um doubtful it will work.

TL: DR - Several of my beers have stuck fermentations even with good pitching rate and probably good enough aeration. Need help!

Any thoughts or advice would be greatly appreciated!

 

[beertroll]

What brand of yeast do you typically use?

 

[ctdenney]

Usually Safale us-04 or 05 depending on the beer. I used Danstar Nottingham ale yeast for a recent oatmeal Stout I did.

 

[FastAndy]

What are you using to measure your gravity? Refractometers will read incorrectly if there is alcohol present, it could be a faulty hydrometer if that is what you're using?

 

[ctdenney]

I have been using a dual scale brix and gravity refractometer. I had no idea they would read wrong with alcohol. Do they read high or low? Is there a standard way to correct them?

If that is the problem, I will simultaneously breath a huge sigh of relief and get massively annoyed that I have put so much time into worrying about and trying to fix this problem over the last couple of months.

 

[FastAndy]

Here is a dscussion on the subject. I dont use one so i am really no help with that question.

https://www.homebrewtalk.com/f11/refractometer-correction-325828/

 

[beertroll]

That must be frustrating. Extract + dry yeast + consistent mid 60's temp should be pretty foolproof. Hopefully somebody wiser than I will pop in here shortly. What do you use to clean and sanitize? I seem to recall reading that bleach can screw with your yeast if you aren't insanely diligent about rinsing. Another thing to check might be your water; I've recently learned what a difference it can make myself. Maybe try a batch using all bottled water? Sorry I can't be more useful.

Edit: Didn't see FastAndy's post. He's probably spot on.

 

[ctdenney]

Assuming I am using the calculators correctly, it seems like the refractometer is 100% the problem, and the corrected values are all quite a bit lower. Problem solved! Thanks

 

[FastAndy]

Cool. Glad to hear its something simple and not a major issue.

Cheers!