Breakfast Stout with US-05 Stalled

[Brewshna]

Hi Guys,

our next try at a bigger stout has once again failed.
We watched the whole process carefully, especially the mashing temp.
We had no problems or mistakes that i can think of.
Pitched 4 packs of 05 at about 22°C. Aeration by vigorous overhead shaking of the fermenter before pitching the rehydrated yeast.
OG Was 20.4P (1.084) and FG should be 4.6P (1.019), after 3 weeks and two following same measurements of 7.2P (1.029) its as far as it will go.
I'm wondering if Aeration is lacking for that Gravity but im just not sure where the problem lies.
Any ideas?

The Recipe: Brewfather

Thanks
Matt

 

[VikeMan]

I don't know where the expectation of an FG of 1.019 came from, but IMO it's probably not realistic. I put your grain bill, mash paramenters, and yeast strain into BrewCipher, and for an OG of 1.084, it predicts an FG of 1.027, which is very close to the 1.029 you're at. The main drivers are your relatively high mash temperaure and relatively unfermentable grain bill.

 

[Brewshna]

That does sound right...
I followed this clone recipe, and used the OG/FG given by Brewfather

 

[Miraculix]

You mashed at 68c, this results in lots of unfermentable sugars. Next time, mash at 62 and possibly also half an hour longer and you will have a lower fg.

Your current stout is probably still nice, just a bit more body and flavour.

 

[Brewshna]

The recipe called for a 68C mash, I think most stouts do. Our mill is rubbish, that probably caused our OG to be a bit low.

 

[Miraculix]

The recipe called for a 68C mash, I think most stouts do. Our mill is rubbish, that probably caused our OG to be a bit low.

Depends. If you want a high fg, you got to mash high, as you did. But don't complain about a high fg afterwards. The fg listed in the recipe is unrealistic with the given mashing schedule. Bad recipe imo.

If you want a strong stout with a lower fg, use 90% pale, 8% roast and rest crystal (you can skip the crystal if you like). Mash @ 62 c for 90 minutes and enjoy the higher fermentability!

 

[Brewshna]

Ok, still learning the trade. Thanks for the answers.
Just one more, would aerating the wort with pure oxygen have helped with the FG at all? (Probably not if the sugar isn't fermentable)

 

[Miraculix]

Ok, still learning the trade. Thanks for the answers.
Just one more, would aerating the wort with pure oxygen have helped with the FG at all? (Probably not if the sugar isn't fermentable)

Maybe a little bit, but the effect would be probably minuscule.

 

[Brewshna]

Weird about the recipe, its a bought BYO Magazine clone Recipe

 

[Miraculix]

Weird about the recipe, its a bought BYO Magazine clone Recipe

Looks much too complicated for me. Keeping things simple results in better beer. There's no need for three different roasted malts for example. Looks a bit like someone tried to get fancy.

 

[VikeMan]

Weird about the recipe, its a bought BYO Magazine clone Recipe

A problem is that most recipe build software doesn't care about the makeup of the grain bill when predicting attenuation, and many of them don't care about mash parameters, but people tend to trust the answers anyway. I've seen plenty of unrealistic FGs in magazine print. "My stout didn't reach its expected FG" is a common enough forum thread that it practically deserves a sticky.

 

[jerrylotto]

One thing that helps with big beers is to ease the yeast into action. Make a starter, even with four packs, to make sure it's all hydrated and active by diluting some of your wort with water before pitching.

 

[Brewshna]

The software is a problem, especially for beginners. I know that most specialty malts lack the enzymes for convertion, but thought the enzymes in base malt make up for it. Also that higher mashing temp produces thicker, less fermentable Wort, which brewfather takes into account. Difficult

 

[VikeMan]

The software is a problem, especially for beginners.

Well, it's not as much of a problem if using software that addresses the problem! BrewCipher considers grist makeup when prediction attenuation. At least one other tool has added it too, but I don't remember which one. (It's not BeerSmith.)

I know that most specialty malts lack the enzymes for convertion, but thought the enzymes in base malt make up for it.

It isn't (mostly) an enzyme issue. It's the fact that specialty malts, to various degrees, have already had some of their starches converted into unfermentable compounds (like caramelized sugars, etc.).

Here's a slide from an attenuation presentation I did a couple years ago. The data is derived from trials that Greg Doss (Wyeast) did a while back. There are obviously also (not shown here) factors other than grain bill (i.e. mash parameters, yeast strain), but the chart is useful to understand the relative fermentability of various grain types.

 

[Brewshna]

Great replay, thanks a lot.

 

[Dgallo]

As @VikeMan said, this is an extremely common occurrence on HBT. Recipe kits/posted recipes tend to go on potentials for grains/attenuation and don’t take mash temperature into account. I brew stouts with similar % as this recipe and og, if I mash 68 (154.5*f) I would finish 1.026-1.031 range. I def would not repitch or aerate at this point. Your most likely done and all that will do is add Dissolved oxygen to your beer

 

[Miraculix]

As @VikeMan said, this is an extremely common occurrence on HBT. Recipe kits/posted recipes tend to go on potentials for grains/attenuation and don’t take mash temperature into account. I brew stouts with similar % as this recipe and og, if I mash 68 (154.5*f) I would finish 1.026-1.031 range. I def would repitch or aerate at this point. Your most likely done and all that will do is add Dissolved oxygen to your beer

You forgot a "not"!

 

[Dgallo]

You forgot a "not"!

Fixed. Thanks brother

 

[couchsending]

You don’t need too add O2 with dry yeast. And making a starter sign dry yeast can actually decrease the viable cell count.

Next time make a little beer first and use the slurry.

Your milk might be no bueno but your efficiency also goes way down with larger grain bills. Happens to everyone. Also in my opinion most calculators overestimate the sugar contribution of oats.

That being said a FG that high is not necessarily a bad thing. The highest regarded Robust Porter in the worldis 7.5% and finishes at 1.030. Most higher ABV roasted beers these days finish much higher than that. Some even finish as high as 1.080...

 

[VikeMan]

^ Just to hopefully avoid confusing @Brewshna, the issue he was concerned about was a higher than expected FG, i.e. not an efficiency problem (due to grain bill size) or an issue with expecting a higher yield from the oats.

That being said a FG that high is not necessarily a bad thing. The highest regarded Robust Porter in the worldis 7.5% and finishes at 1.030. Most higher ABV roasted beers these days finish much higher than that. Some even finish as high as 1.080...

I do variations on a "Pastry" Stout where the base beer's FG is right at 1.050+-.001. They tend to be popular with the kids at brewfests.

 

[superiorsat]

I personally don't take much delight in drinking overly sweet beers. I would taste it and if it is too sweet I would feed it a little honey to get it going and through in fresh pack of US-05 to get some fresh soldiers on the job. I think you could probably shave a few points off of where you are now ( done it enough times to know it works and basically always plan on feeding big beers to get them across the finish line, not that I would consider this beer particularly big). You aren't even at the abv yet for the recipe so you might just as well feed it and get it going again to see what happens. Luckily this has coffee in it and if your end product is still to sweet add more coffee to offset the sweetness. Sometimes just 2 to 3 gravity points makes all the difference.

 

[Brewshna]

Tasted the measurements and yes a bit sweet, but not too bad. 2 months in a secondary, just getting there before bottling should help mellow everything a bit

 

[Brewshna]

So I love big stouts and would love to brew a 12% chocolate stout in a vault city style. massive chocolate without too much sweetness. how do I brew a big beer like that on my 30l system? usually do the 4gallon batches and guess I'd have to reduce output for much bigger beers with a lot of body.

 

[Brewshna]

or reiterated mashing, which I still have questions about

 

[davidabcd]

As mentioned, that's about where it should end up. The only difference in my experience is my OG is above 1.100 for those types. I was put off the first time I did a Dragon's Milk clone (1.030 FG) but my OG was 1.110.

 

[superiorsat]

On big beers like 12%-er's with your 30L equipment you could do 2 mashes and just take first running's maybe save second running's for a parti-gyle beer if you did a back to back brew. You could also up the gravity with extract in the boil. You could feed the yeast during fermentation to get to 12% that is how I use to do it back in the cooler mash tun days. IME stouts that big have plenty of body ( for me but I don't want to cut a beer with a knife either ) even without mashing at high temp. I mash those at 150F which helps on getting the FG down to not cloying sweet area and again I always plan on ( factor in to my SG ) feeding the yeast to make sure they get the job done.

 

[Brewshna]

what do you mean by, "feeding the yeast"?

 

[VikeMan]

what do you mean by, "feeding the yeast"?

He means starting with a wort that would normally finish at something less than 12% and then give it fermentable sugars incrementally after most of the initial fermentation is finished.

That said, I have made 12%+ ABV stouts and have never incrementally fed any of them. Pitch an adequate amount of healthy yeast, oxygenate the wort thoroughly (if using liquid yeast), use a yeast nutrient (maybe not absolutely needed, but I do it), and use a yeast strain that has a typical ABV tolerance higher than your target, and shouldn't need to feed incrementally.

 

[superiorsat]

I don't think it is required either but I don't necessarily feed to try to get to 12+.just saying with his limited capacity it is one way to go. Feeding close to the end is just a habit I've got at the moment on big beers because I think it helps finish quicker. 3 weeks max for any beers I make and anything under 10% usually gets kegged on day 13. Lots of ways to go about this process, part of the reason it is so fun. Lots of good info for Brewshna on this thread.

 

[VikeMan]

Feeding close to the end is just a habit I've got at the moment on big beers because I think it helps finish quicker.

I have some doubts that adding simple sugars actually encourages the yeast to finish the remaining (complex) sugars, which are pretty much all maltodextrin at/toward the end. It's a significantly different chain of events (metabolically) for the yeast. But if you think it helps, I won't say that you shouldn't do it.

Just be aware that adding (say) a pound of table sugar to a 5 gallon batch will result in an FG a little more than 2 points lower, just from the fermentation of the added sugar (i.e. not the residual sugars), because of ethanol being less dense than water.