Stuck fermentation after addition of cane sugar and candi syrup?

[Carter1932]

I made 10 gallons of Dubbel a couple of weeks ago. I wasn't real sure when would be the best time to add 1/2 lb of cane sugar and 3/4 lb of dark belgium candi syrup to the wort per 5 gallons batch. After some searching on this site I went with a recommendation of adding just as the krausen begins to subside. The logic behind the decision was to allow the yeast to work on maltose before adding more complex sugars to the mix.

Its been a week since I added the sugars; initially the krausen increased for about 36 hours, then it died back to a small bubbles on surface. Currently there is little surface activity however the airlock continues to release CO2 regularly.

In the last couple of days I checked the specific gravity on each of the 5 gallon carboys, one is at 1.028, and the other is at 1.030 @ 70 deg. Unfortunately I did not take a gravity reading before I pitched the sugar.

My question is, should I repitch my yeast (Belgium Ardennes 3522), wait longer and then repitch, or not repitch at and all be patient.

I am interested in any advise you may have on using candi syrup and how yeast reacts to it. Is it normal for it to be slow fermenting. Will final SG be higher than what I'm expecting, ie 1.010 or less.

Thanks!

 

[david_42]

What was the OG and recipe?

 

[Carter1932]

Recipe:
21 lb. Pilsner
2 lb Munich 10L
1 lb. Special B
1 lb. Aromatic
1 lb. Caramunich
1.5 lb. Dark Belgium Candi Syrup 80L
1 lb. Cane sugar

3 oz. Tettnang hops added with 60 minutes left in boil.

Pitched 3/4 gallon Belgian Ardennes

Mashed for 90 minutes @ 149˚

Netted 12 gallons pre-boil.

Boiled for 90 minutes.

Added Irish Moss w/ 15 minutes left in boil.

Netted 10.5 gallons post-boil.

OG: 1.0567 (before addition of sugar)

Began fermentation @ 63˚, slowly raised it 70˚ over next week.

One week in I added 1/2 lb cane sugar and 3/4 lb candi syrup to each 5 gallon batch.

After two weeks SG is around 1.028.

BTW - The software I'm using (Brewtarget) says I should expect a FG of 1.019. So maybe I should just be patient and wait a bit longer. Not sure I should completely trust the software and I"m not used to finishing at such a high gravity.

 

[Hermit]

Software makes 'assumptions' with the FG. No one seems to be able to come up with a reliable model for how much fermentables you get based on mash temp for example. This also becomes a 'problem' when figuring IBU units needed since the residual sugar is what you are balancing with the hop bitterness.

 

[rockfish42]

Give it a couple of swirls and raise the temp a little higher, I wouldn't worry until it's been 4 weeks at least.

 

[ReverseApacheMaster]

You can try raising the temperature up to the mid-high 70s. It will probably dry the beer out a little.

That dark candi syrup may have more unfermentables than your software predicts. Have you tasted it? Is it cloyingly sweet? If it is not, then you have run out of unfermentable sugars and fermentation is just done. If it is too sweet, try raising the temperature and give it more time.

 

[Carter1932]

I've raised to 73˚ and percolation of airlock has increased considerably.

I've tasted it, it is a bit sweet. I'll just wait it out and see how it goes after a month.

 

[Carter1932]

Well after just one additional week @ 70 - 73 degrees this brew has dropped 10 points. So it appears all is well (taste good too!)

I think if I do a similar brew in the future I'll probably spend a bit more time oxygenating the wort and add some yeast nutrient.

 

[ReverseApacheMaster]

I'm glad it worked out. I think you make a good point about the yeast nutrient. It would probably help avoid a stuck fermentation by adding nutrient along with the sugar.

 

[logan3825]

When I made a dubbel I added the candi sugar with 15 minutes left in the boil.

 

[Fetus]

When I made a dubbel I added the candi sugar with 15 minutes left in the boil.

You boil off a lot of the aromas when you add sugars to the boil. It's best to add them during fermentation.

 

[logan3825]

Good to know for next time. Honestly though I am not to worried about much boiling off in 15 minutes. It took a good part of that 15 min until it was all dissolved.