Belgian fermentation stalled

I am brewing my first fairly high abv beer. It is  the Belgian Honey kit from Midwest Supplies.
7# Pale Malt
4# Wheat
8 oz Cara 20
8 oz Carpils
1# Candy Sugar
1# honey

2 oz Liberty @ 60 min
1 oz Styrian @ 2 min

1 tbs. Coriander @ 5 min
.5 oz bitter orange @ 5 min

1 Package rehydrated T-58
OG 1.078
FG 1.020

I pitched low (at 64 degrees)and slowly ramped up to 70 over the course of a week. On day nine I gently stirred the fermenter to get the yeast back in suspension and raised the temperature to 72.
Should I add a clean yeast such as US 05 to help get the FG down to a lower number? I’m hoping to hit 1.015 at the very least. Am I just stuck with what I have ? I think that I under pitched.

I would wait.  Sometimes bigger beers take a while to finish, especially if you underpitched.

What temp did you mash at?  Did you aerate the wort?

I definitely think you underpitched but that T-58 is a beast. You still got 74% apparent attenuation which probably means the yeast is just done. With some aeration and better pitching rates you might have pushed that FG down a few points but probably not down to 1.015.

Does the beer taste too sweet or are you just targeting 1.015 because you think you should? If the beer is too sweet then you need to pitch another yeast strain to push down the gravity. I would opt for 3711 or the Belgian high gravity strain. But first I would give your yeast another 5-10 days to see if they do any more fermentation on their own.

I mashed at 152. I’m getting my target FG from Beersmith. The sample didn’t taste overly sweet to me so I guess that’s what matters the most.
I relied on the kit instructions for the amount of yeast to pitch. Next time I’ll check Mr Malty.
I did aerate by stirring with a wisk. I probably could of done a better job with aeration.

Would US-05 be a good idea to bring the FG down or is it better just to call this one done when I get a steady reading?

If T-58 was pitched into wort and finished up at 1.020, there’s no reason to think that US-05 is going to do any better in an environment that has a lot more alcohol and a lot less O2 and sugar. It’s generally not worth it to pitch a new yeast unless there’s some reason to think your yeast kicked the bucket way too early and the wort is still pretty sweet and low in alcohol.

If you really want to give it a shot, then your best chance for success is to pitch a starter at high krausen of a yeast that is both attenuative and alcohol tolerant. WLP099 is an option. WY3711 could work in a Belgian beer, but that may backfire and drive your FG all the way down to the mid single-digits.

You could also go the long route and pitch Brett, then sit on it for another year or two. That has the potential to yield fantastic results.

TL;DR - if it doesn’t taste horribly underattenuated you’re better off leaving it alone

If it’s only 9 days, I would just wait.  Denny has some rule of thumb about the last certain % (5%?)of attenuation taking as long as the first 95%.  I have found that to be accurate as I have also found that underpitched big beers take a long time to reach terminal gravity.

There is no harm in patience.

9 days is generally too soon to do anything with a beer that big, although as long as it tastes good there’s no real harm in kegging. For bottling, though, that could be dangerously under-attenuated. Almost 20% simple sugars means that that attenuation limit of the wort would have to be around 60% for it to be finished at 1.020.

Did you add the sugars in the kettle? I’ve had problems with Belgian strains under-attenuating beers with a large proportion of sugar unless I add it to the fermenter.

I am worried about bottling. I don’t keg.
The sugar and honey were both added in the boil.

I just made a similar beer with T-58…I don’t think I like that yeast lol.

O.G. was 1.076, aerated and pitched at similar temp to OP and started ramping up a couple degrees a day after fermentation slowed.  Took reading of 1.038 on day 7, took out of ferm chamber and moved to warmer part of the house.  Fermentation kept kind of starting and stopping over next couple weeks, took another reading on day 28 (the longest I am willing to go before transfer) and reading was 1.027.  Transferred off yeast into keg, still looks like there is quite a bit of yeast in suspension.  I figure I’ll put it on tap after a few days…either it gets a few more points before I tap it or I’ll live with it or dump it.  :-\

The idea of using Brett sounds really interesting. I haven’t explored Brett at all. What would I have to do to age a beer for 2 years? How much would I pitch. I’m not even sure where I would get it.

you can order it from most online shops. All the major yeast labs and most of the small ones as well carry a few varieties of brett.

You would transfer to a carboy or other vessel and pitch the brett. put it somewhere dark and cool and make sure the airlock stays full.

no real danger in leaving it alone on the yeast longer than 28 days. I do that a lot with big beers and lagers. patience will be rewarded.

A question for both of you, did you take your final readings with a hydrometer or a referactometer? if the latter have you adjusted your readings for the presence of alcohol?

I used a hydrometer for my reading.
If I age it for a year or more I think I need to put a blanket of CO2 over it . Because I don’t keg I’m not sure how to easily get CO2.

luckily for you brett produces co2 during metabolism and the beer you are racking to secondary is full of disolved co2 some of which will come out of solution as you rack it thus creating a new blanket of co2 as far as that goes. I’ve aged plenty of beers in carboys with for months and month without purgeing and not had issues with oxidation, sour beers especially so.

Will I need to use a glass carboy to minimize oxygen transfer? What is the ideal temperature? I have a place in the basement that will stay in the 65-70 range over different seasons.

As a non-kegger I also have no CO2 tanks laying around to flush fermentors before racking over. Any time I rack a beer to a new fermentor for aging/souring/brett I make a solution of priming sugar and dump that in the fermentor before racking in the beer. The yeast in solution will ferment the sugar and in the process slurp up any oxygen that made its way into the beer during racking and push out the oxygen in the headspace with the CO2 from the fermentation. It’s not perfect but it’s better than not doing anything. Eventually brett will form a pellicle and regulate oxygen exposure for me but until that happens that CO2 layer will buy some time. I’ve had beer sour for two years under that process and it’s worked reasonably well.

glass carboy or stainless is best but plastic is okay if that’s what you have. the better bottles I think are more resistant to o2 pickup than the buckets.

Thanks everyone. I’ll let this sit for at least another week and see where the FG ends up.
It looks likely that I will be brewing my first sour soon,

Learned alot just by reading this thread . Tnx .

If you do go the brett/bacteria route, be sure to use a secondary vessel that is appropriate for your batch size (i.e. a 5 gallon carboy is best if brewing that size batch).