Help troubleshooting first BIAB stout!

[Brewer #330687]

Hi all,

Attempted my first all grain BIAB yesterday - tried an oatmeal stout. I developed the recipe from all the recipes I've seen, and tweaked it based on the grains I had on hand.

Couple of things went a bit wrong - most importantly, my OG was much lower than what it should have been - 1.036 instead of 1.057 (maybe cos I sparged? Is this complete brewer noobage? )

Secondly, the wort (right after mashing, before the boil) was extremely oily to the touch! Was a bit surprised...don't know if this is normal for the grain bill or something went very wrong. After the boil it has reduced significantly but there is still a slight oiliness to it.

I mashed at 67 C for 60 mins, lost 10 degrees so mashed for another 15 mins. and then mash out for ten mins at 74 C.

Grain bill: (8L batch. Mashed 2kg grain with 6L water, sparged with 2L. topped up to 9L for boil)
Pale (Belgain) malt - 70%
Crystal 55L - 5%
Flaked oats - 16%
Chocolate malt - 4.5%
Roasted barley - 4.5% (I didn't mill this..don't know if this is bad as well)

I'm sure me error is staring you in the face from my description above...but I need it to stare me in the face!

Look forward to your expertise!

 

[Megary]

Just curious...

How did you measure your OG and what was the temperature of the sample?

 

[Brewer #330687]

Just curious...

How did you measure your OG and what was the temperature of the sample?

Have a standard SG hydrometer. ...cooled the sample down to 35 C and measured. Thanks!

 

[Craigerrr]

Most hydrometers are corrected for closer to 20C.
Was there a reason for not crushing the roasted barley?
Possibly crush was not fine enough.
Sorry, can't comment on the oily feel.

 

[Brewer #330687]

Most hydrometers are corrected for closer to 20C.
Was there a reason for not crushing the roasted barley?
Possibly crush was not fine enough.
Sorry, can't comment on the oily feel.

Thanks for the reply. I guess I'll be more mindful of temperature next time I measure SG. Not crushing the roasted barley - I'm not sure....I think I read or saw a video where they said roasted barley need not be milled since it's unmalted. Don't know if this theory holds..Thought I'd go with it just as an experiment. I guess milling it next time would be better?

 

[Megary]

So correcting for temperature, your OG was probably 1.040-ish. Definitely check to see what temperature your hydrometer is calibrated for. Then use the calculator on this site (under Tools) to correct the gravity.

I would guess the oily slickness probably came from the Flaked Oats, but again that is a guess. I’ve used Oats before, but not to 16%. That percentage of Flaked Oats *could* cause a bit of a head retention issue in your finished beer, but again that’s not a certainty.

As @Craigerrr pointed out, the most likely cause of the low OG is from a grain crush that wasn’t fine enough. My first BIAB, I missed my OG by half a mile. Next time I crushed a lot finer and hit my numbers dead on. You’ll dial it in.

Check this post out when you get some time.

https://www.brewersfriend.com/forum/threads/biab-crush-experiment.12411/#post-94912

 

[Brewer #330687]

So correcting for temperature, your OG was probably 1.040-ish. Definitely check to see what temperature your hydrometer is calibrated for. Then use the calculator on this site (under Tools) to correct the gravity.

I would guess the oily slickness probably came from the Flaked Oats, but again that is a guess. I’ve used Oats before, but not to 16%. That percentage of Flaked Oats *could* cause a bit of a head retention issue in your finished beer, but again that’s not a certainty.

As @Craigerrr pointed out, the most likely cause of the low OG is from a grain crush that wasn’t fine enough. My first BIAB, I missed my OG by half a mile. Next time I crushed a lot finer and hit my numbers dead on. You’ll dial it in.

Check this post out when you get some time.

https://www.brewersfriend.com/forum/threads/biab-crush-experiment.12411/#post-94912

Thanks a lot Megary! That's really helpful. Didn't think it would be the grain crush of all things. Had it milled by the seller himself cos I don't have a mill. I'll experiment a bit, and meanwhile I'll check out the link. As for the oiliness...as you said, it might be the oats...nothing I can do now - hopefully post fermentation it reduces. Thanks again!