Can I fix a high FG after kegging?

[Nagging Wife Brewery]

I just kegged a 5 gallon batch of an English brown this morning and took a sample during the process but didn't drop a hydrometer into it until after I'd kegged and poured in gelatin. I was expecting an FG of maybe 1.014 based on BF but got 1.017 and it does taste a bit sweet - but maybe this truly is just the unfermentables. I was thinking I'd leave it refrigerated for a few days to let the gelatin do its thing and then pull the keg out of the kegerator to raise to room temp and hope the yeast go back and finish their job. Any thoughts or other recommendations?

A little more info - this is just the Nutcastle recipe from brewing classic styles. 9.75# Maris Otter, .5 Victory, .5 Crystal 40, .25 Pale Chocolate, .75 Special Roast. I mashed a bit higher than the recipe starting at 157.6 and dropping to 154.6 over an hour. Iodine test was positive. Yeast was Wyeast 1028 London Ale and this was my first time with this stuff. I did a healthy starter based on MrMalty and the BF calc. I did oxygenate with pure O2 for 60 seconds at a very slow simmer (don't have an O2 regulator). OG was 1.052. Fermentation showed signs about 12 hours in and was vigorous at 24 hours - one of the most active I've seen in terms of bubbles and obvious movement within the wort. There was very little krausen so I didn't lose any yeast to the blow off tube. After about 36 hours all bubbling had stopped. I feel like I can tell as the cloudiness of the yeast begins to fall in the carboy and it appeared this was happening so after 48 hours I began pushing the temp up from 67 to 69 over the next 48 hours. My experience just told me fermenation was done and I had the next batch I was itching to make. I held at 69 for another day and then began cold crashing to prep for kegging and fining. Total time before cold crashing was just under 6 days.

So, will my solution possibly work or based on my details do I not really have a problem? I'm a little in the dark as there were several new variables for me in this brew - never used 1028 before, never mashed this high, and never really under-attenuated before.

 

[Ozarks Mountain Brewery]

based on that info at 70% I come up with 1016 final gravity in the calculator, I would say that that yeast only has a 70% attenuation and is med to low Flocculation meaning it needs more time to clean up and condition, mix that with your temp and Id say you found the issue, I would have done 2 things ferment longer and mash no higher than 154 max, the only way to fix it is to leave it in the keg but warm back up to room temp, add a pack of champagne yeast and wait another week, it will might even carb as well as eat more sugar

 

[Nagging Wife Brewery]

Interesting on not mashing high with a yeast like that. I didn't mention it before but I got more volume on this batch so I ended up putting about .75 gallon in a 1 gallon jug fermenter with some dry yeast - Nottingham. This is still in the fermenter right now. I think I'll leave it there for a total of 2 weeks before bottling and checking FG on that. We'll see if it did a better job than the 1028.

 

[Yalc]

I would not worry about a few points either way but if you are you could cut it with a little boiled and cooled water. Use a dilution calculator to get the amount, like the one on this site.

 

[Nagging Wife Brewery]

Quick update on this one. I did let the keg raise to room temp (about 68) and then pitched a packet of dry champagne yeast (not rehydrated). I gave it a week and then carbed it up over about 4 days. Taking a sample and degassing, the FG hasn't changed at all. I've found that the flavor has gotten better though. I've slowly increased the carbonation over the typical 2.0 volumes or so (for this style) to lighten up the body a bit so it's pleasant now (and sessionable at about 4.6%).

The smaller fermenter that I fermented with Nottingham came out with the same FG so I don't think yeast strain is the issue.

Based on an English Barleywine I did after this batch, I'm wondering if it's not mostly my process as it ended up with a higher FG as well. I've been overheating strike water and then letting that pre-heat my cooler mash tun for 15 min before douging in. I've been aiming higher recently after switching thermometers to a thermapen and discovering my old floating thermometer had me mash several degrees lower than I thought. After adding my grain, I've been 2-3 degrees over mash temp and spend 5 minutes getting the temperature down to a degree over recipe mash temp as I'm consistently losing 2.5 degrees or so over a 60 min rest. I've heard most of conversion happens in the first 15 min so if that's the case, I may be getting a far more dextrinous wort than I was thinking.

I'm going to try and hit much closer to mash temp on my next brew in a few days - an Enjoy by IPA clone. Gotta have a very fermentable wort on this one so hopefully this change makes a difference.

 

[Head First]

Mash temp makes a difference for sure. You can mash as low as 149 or as high as 158 so for a more fermentable beer don't hesitate to drop the temp down to say 152ish. It would still be within the mash range when finished. I mash for creame ales or crisp beers at 149 but even for imperial stouts very seldom go above 156. Most of the grain we buy now is fully modified so starting mash temp would affect the outcome.