Why Can't I make a dry Dry Stout?

[pherball]

So i've brewed about 5 batches of dry stout and have never reached an attenuation level above 70%.

On this last batch i pulled out all the stops to achieve a more attenuated beer. I did a short protein rest (120) before infusing up to 150 for a 90 minute conversion rest; After repeated batches of white labs irish ale yeast, i switched to s-05 (one packet), it was fresh and hydrated before pitching; i used a yeast nutrient; i oxygenated with pure oxygen; i maintained a consistent fermentation temp of 68.

So what gives? My recipe was standard: 10% Roasted Barley, 25% Flaked Barley, the rest 2-row.

After switching yeasts and achieving no better results, i have concluded it must be the ingredients. which have been constant between each batch.

So which item in my grain bill could be the culprit?

It must be the flaked barley, right? It is from the LHBS. Do i need a different mashing procedure to make it more fermentable?

 

[bernerbrau]

Try doing your alpha rest at 147. That may get you a more fermentable wort. You might also want to add some sugar to up your attenuation.

 

[OLDBREW]

So i've brewed about 5 batches of dry stout and have never reached an attenuation level above 70%.

On this last batch i pulled out all the stops to achieve a more attenuated beer. I did a short protein rest (120) before infusing up to 150 for a 90 minute conversion rest; After repeated batches of white labs irish ale yeast, i switched to s-05 (one packet), it was fresh and hydrated before pitching; i used a yeast nutrient; i oxygenated with pure oxygen; i maintained a consistent fermentation temp of 68.

So what gives? My recipe was standard: 10% Roasted Barley, 25% Flaked Barley, the rest 2-row.

After switching yeasts and achieving no better results, i have concluded it must be the ingredients. which have been constant between each batch.

So which item in my grain bill could be the culprit?

It must be the flaked barley, right? It is from the LHBS. Do i need a different mashing procedure to make it more fermentable?

25% flaked barley is a lot for a dry stout IMHO. You really need to post the recipe but, if you did something like this You may like it
5 gal. batch 70% eff.

7.5# english 2 row pale malt
1# roasted barley
1# flaked barley
8oz flaked oats

use english fuggles and ekg for hop additions

1084 irish ale yeast with starter @ 65-68

single infusion 152-154*F or 50-60-70c multi step mash

might want to add some gypsum to your brew water
Edit: some irish moss 15-20 mins. B-4 boil ends.

 

[niquejim]

Try this
https://www.homebrewtalk.com/f68/irish-owl-dry-stout-58364/

 

[Hammy71]

Check your water quality/ph. My stouts always finished high when I used my tap water. I now mix half tap/half RODI water in all my brews and I hit my FG pretty consistently now. My stouts have reached a new level. The roasted barley will play havoc with your ph, and that could be screwing up your brew.

 

[brewt00l]

Dry stouts are one of my favorite beers to brew...my recipe consistents:

70/20/10 grain bill w/ 2 ounces of acid malt thrown in
Single infusion, mash 150 for 60m
~36IBUs, Williamette or EKG @60
WLP007

Just say no to Irish ale yeast, oats, caramel and chocolate malts in your recipe

 

[pherball]

Check your water quality/ph. My stouts always finished high when I used my tap water. I now mix half tap/half RODI water in all my brews and I hit my FG pretty consistently now. My stouts have reached a new level. The roasted barley will play havoc with your ph, and that could be screwing up your brew.

how does water chemistry affect attenuation?

I do use 5.2 stabilizer in all my batches, although i have never checked my mash ph.

Also, i profiled dublin-like water with R/O and salts

 

[Hammy71]

Not sure of the science behind it...just my personnel experience. A quick Google search came up with....

http://www.danstaryeast.com/library/water_chemistry.html
http://www.annapolishomebrew.com/REferment.asp

Maybe it's not the Ph that's my tap water's problem....but the RODI seemed to help my immensely