High Final Gravity on my Stout

[Fuzzy-felt]

I wondered if anyone might be able to offer any advice on a problem I have with my latest brew please.

I have bought BeerSmith2 and got hold of a recipe called Velvet Stout via the website. I converted this to an extract recipe, and made adjustments to give me a final volume of 23l all via the BeerSmith2 software. About 14 hours after pitching the yeast a vigorous fermentation took place, which lasted for 3 to 4 days. 7 days in the hydrometer reading was 1.029, and now, 12 days after pitching the yeast, the reading is still at 1.029.

I've read about potential problems that might cause a fermentation to stick, but I wondered if the inclusion of 750g of lactose might have anything to do with this. The inclusion of this lactose has an effect on the estimated OG and ABV within Beersmith2: including lactose OG=1.056 (it was actually 1.061), ABV=6.0% (which I think means the FG is 1.010); omitting the lactose gives OG=1.047, ABV=4.5% (an FG of 1.013 I believe). I'm finding this odd because I have since discovered that lactose is largely unfermentable, so why would BeerSmith2 show this large difference in ABV values for including/omitting the lactose?

Anyway, could it be that fermentation has taken place to the 'correct' level, and it is all of this lactose that is causing my FG to be so high? It just seems so very high, though, and the software is showing that the addition of lactose only adds 9 points to the OG.

Here are the ingredients:
250g Special - Black Malt
250g Special - Chocolate Malt
225g dark Crystal Malt (400)
3.35kg Light LME (Cedarex)
750g lactose
50g East Kent Goldings hops
32g Styrian Goldings
Wyeast West Yorkshire 1469 (smacked and expanded a lot before pitching)

I sit the fermenter on a heating pad which keeps the temperature at about 22C.

I would appreciate any thoughts on this matter.

Regards,

Mark.

 

[graysalchemy]

I would say that you have got a stuck ferment. Have you tried giving it a gentle stir to rouse the yeast?

 

[jonnymorris]

Don't know about the lactose but I agree with GA... it's got all the hallmarks of a classic stuck brew.

 

[Fuzzy-felt]

Thanks for the responses.

I've not had a stuck ferment before, and wasn't entirely sure that this is what I might have. I'll try giving it a gentle stir and see what happens. I did harvest some yeast from the period when the krausen bubbled up quite heavily. This wouldn't have deprived the brew of yeast it needed, would it?

One other thing I recall is that when I had all of the wort in the fermenter the temperature was a little too high. It was late and I went to bed, and didn't pitch the yeast until early next morning, but I forgot to aerate the wort first. Possibly significant?

I also ordered some alcotec re-start yeast and yeast nutrient yesterday in order to try to get things moving again (following instructions on The Home Brew Shop's webpage). The package arrived today, but not the re-start yeast as it was out of stock. Hopefully it'll arrive soon.

The lactose aspect of my query remains a bit of a mystery, though.

 

[Fuzzy-felt]

I've just discovered from the BeerSmith forum that there appears to be a problem with the software when it comes to dealing with lactose, and it treats it as highly fermentable (which it isn't). It's on the to-do list for an update, apparently. How ironic that my first brew since buying BeerSmith 2 is laced with the stuff. Looks like my beer is going to be a lot weaker than originally anticipated (if I ever get it to ferment properly).