Adding sugar to primary fementer

[loovenator]

I need a bit of advise on adding sugar to a primary fermenter, here's the issue at the moment.
I've brewed this delicious looking milk oatmeal stout (https://www.homebrewtalk.com/f68/milk-oatmeal-stout-182975/) that had an OG of 1.044.
It has now stabilised down to 1.022 after 5 days (the fermentation seemed to drop off after about 36hours).
The recipe had an OG of 1.052, which we were quite far off so this brew is going to turn out to be a low ABV of about 2.89%.
I understand that the ABV can be boosted by adding sugar to the primary fermenter and I'm looking to get it to about 4-4.5%, how much sugar do I need to add to achieve this?
Also, as it's been in primary for 5days am I too late to get any activity from the yeast? If so, can I just re-pitch more yeast and sugar?
Cheers.

 

[loovenator]

Btw, this was a 5 gallon batch.

 

[Chadwick]

I looked at your recipe and it looks like you have a ton of unfermentable sugars in there and very little fermentable sugars. At anyrate, I'm sure that the gravity will drop a bit more if you allow it time, say 2 more weeks in the primary. I think you can get the gravity down to 1.018 or somewhere really close to that.

Still, I expect you want less sweet and more ABV. So, yes. You can add more sugars to the primary and the yeast will eat away at them, but you won't get the final graviy much below 1.018 because the unfermentable sugars will remain unfermentable sugars. Also, Windsor yeast has a rather lower attenuation rate compared to many other yeasts.

If I was you I would mix up some pretty strong wort and pitch it into the primary along with a shot of some high-attenuating yeast strain. This will get you more ABV and if you use a nice clean yeast, like US-05, it will not alter the flavor profile much at all.

Another alternative, although this will alter the style, is to pitch some Saison yeast. I've found that many Saison yeasts will actually consume some sugars that would be unfermentable for other strains of beer yeast. However, Saison yeasts will leave a definite taste profile that would be out-of-style for what you are trying to make. Also, allow plenty of time to bottle condition anything brewed with a Saison yeast. Time makes the funny flavors go away.

Lastly, you can pitch some wine yeast in there. Wine yeast will tear through some of those sugars too. However, I do not recommend this at all. It won't taste right at best, and will taste super-icky at worst. The latter is most likely.

What I would do:
Notice my avatar, there is a reason for that. If this was mine I'd use it as an oppertunity to experiment with that Super-Yeast that supposedly can go to 25% alcohol. I'd keep adding strong concentrations of really dark wort until I get the ABV up to around 18% and then bottle for an experimental Imperial Stout. Give it at least 6 months to age in the bottle, and if its good....bam! I've got Christmas presents for all my friends and family that love good beer.

 

[flars]

If you added all of the fermentables, the DME, your OG would have been 1.041. The pound of lactose would have brought the OG up to about 1.052.

Are you sure of your OG reading? Was it temperature corrected? Was this a full boil or a partial boil? If this was a partial boil, the wort and top off water may not have been well mixed when you drew your hydrometer sample.

If the volume in the fermentor is 5 gallons, and you added all the ingredients including the lactose, I don't think missing the OG of 1.052 is possible.

 

[JKaranka]

Those are roughly the all the right figures for Mackeson Stout, one of the early milk stouts from 1909. They dropped two years ago the abv from 3% to 2.8%.

Some gravities here:
http://barclayperkins.blogspot.co.uk/2010/09/mackeson-details.html

 

[loovenator]

Thanks for the quick responses all.
Chadwick - with what I have at my disposal at the moment I think I prefer the sugar option. I've read a few things online that suggest I could bump my ABV up by about 1% which would be ideal.
For this 5 gallon batch would I need to add as much as 2kg of sugar? Or is that too much? I understand you don't want to add more that 20% of your total fermentables.
I do like your experimental Imperial Stout idea but it's just a little too radical for my 3rd beer. Plus I'm a bit impatient so maybe that's something to try when I've got a few more beers on hand to keep me company while I wait.
Out of interest, when you say make a strong wort, how much light DME would I need to use to make that and what kind of boil size?
Flars - that's a good point about the hydrometer temp, I hadn't taken that into account. The OG was taken at about 28c so I've made the adjustment (add 0.0029 to OG) and it still only takes me to 0.047 which would give me a 3.28% beer or 3.81% if I hit a FG of 1.018.
The post boil wort size was 15 litres so I had to add 7 litres of cold water when adding to the fermenter, possibly that's why my OG was low? Or it could have been my steeping technique. Either way I'm well off the OG.

 

[loovenator]

JKaranka - I'm in my second month as a home brewer but it's good to see I'm keeping up with a century old recipe.

 

[flars]

..."Flars - that's a good point about the hydrometer temp, I hadn't taken that into account. The OG was taken at about 28c so I've made the adjustment (add 0.0029 to OG) and it still only takes me to 0.047 which would give me a 3.28% beer or 3.81% if I hit a FG of 1.018.
The post boil wort size was 15 litres so I had to add 7 litres of cold water when adding to the fermenter, possibly that's why my OG was low? Or it could have been my steeping technique. Either way I'm well off the OG."

You are not that far off the estimated OG of the original recipe. Wort and top off water not being thoroughly mixed could be the missing points.

ABV - My favorite stout is only 3.9%.

 

[loovenator]

Thanks for your help on this one.
Possibly the best idea was to leave it as it was and be happy with a relatively weak stout but I've opted to add 500g of sugar which I boiled in a small amount of water to sanitise.
The main issue is I don't really know how much this will effect my abv but it seems like now is as good a time as any to try adding sugar to see how it effects the beer.
Btw, I did this the night before last and a krausen formed pretty quickly and had settled down about 8-10 hours later.
The recipe seemed to get rave reviews from everyone on the other thread so if this one turns out nasty I'm going to retry it and make sure to mix the post wort boil and water addition and not add sugar if I miss the OG.
I'll write back in a few weeks to say how it tastes.