Oatmeal Stout

For my second all grain batch I decided to try my hand at a stout.  I made an extract version of a Dry Irish Stout that I really enjoyed and I don't have many bottles left so brewing some more made sense.  The extract beer had roasted barley for steeping which produced a very dry and somewhat astringent taste that I could have done without.  I chose another recipe from homebrewtalk.com (Smooth Oatmeal Stout) based on its stated goal of keeping astringency to a minimum.

As you'll see below it's a pretty complex grain bill.  Percentage wise it's not a lot of roasted grain.  I wonder how much the various specialty grains actually will be noticeable in the final product.  If it turns out well I will probably come back to this and make some minor tweaks.

The brewday went fairly smoothly.  From my last batch I was concerned about my water loss rates.  This time I started with a bit more water (9 gal) and I ended up with about 5.5 gal at the end of the boil which is nice.  I also had very good luck hitting my mash temperatures.  Unfortunately my efficiency was off a little bit.  The original recipe called for 6.5 lbs of base malt with an efficiency of 80% to get an OG of 1.055.  My last batch with less than a 75% efficiency told me I needed to add more base malt (or so I thought) so I went with 7 lbs.  Doing some more reading about efficiency and taking a closer look at my hydrometer I have discovered that the reading needs to be based on a 60 F sample.  I didn't take a temperature of my gravity sample unfortunately.  I believe it was around 80 F.  At this temperature, using water, my hydrometer appears to be under measuring by ~0.005 gravity points which would make the sample ~1.050 rather than the 1.045 I read so that is what I will run with.  Need to do more experimentation on this.

The wort is a muddy brown rather than the black I would associate with a stout.  I wonder if I should have upped the roasted grains a bit to compensate for the extra 0.5 lb of 2 row.  Will be interesting to see where the color ends up when fermentation is complete.

Recipe Details:

• Grain:
• 7 lbs 2 Row
• 8 oz Roasted Barley
• 12 oz Chocolate
• 8 oz Crystal 40 L
• 8 oz Crystal 120 L
• 12 oz Victory
• 1 lb Flaked Oats
• Hops:
• 2 oz of Willamette Hops at 60 min
• Yeast:
• S-04
• Water:
• 9 gal RO water
• 2 tsp 5.2  pH Buffer
• 1 tsp Calcium Chloride
• 1 tsp Irish Moss at 20 min

Process Details:

• Batch Size:
• 5.5 gal (Target 5.25 gal)
• Mash:
• 156 F for 60 min (Target 156 F)
• Boil:
• 60 min
• Fermentation Temp:
• 65 F

Results:

• OG:
• 1.050 (Target 1.055)
• Efficiency:
• 71% (Target 78%)
• FG:
• 1.014 (Target 1.018)
• ABV:
• 4.73% (Target 4.86%)

Brewing Notes:

• 4/13/14 Brew day - 6:00 AM to 10:30 AM including setup and cleanup
• Brought about 5 gal of water up to 185 - took about 20 min
• Added pH buffer to the mash tun
• Added 13.75 qt to the mash tun for a 1.25 ratio of water to grain
• Let the temperature settle for 10 min
• Strike temperature ended at 172 F which is what I wanted
• Added the 11 lbs of grain - made a really focused attempt to ensure I didn't have any dough balls - I don't think this is likely to be a cause of my low efficiency
• After 5 min the mash was at 160 F - the target was 156 F so I stirred vigorously until the temperature dropped.  Measured pH using test strips as between 5.0 and 5.4 (was closer to 5.0)
• Mashed for 60 min - final temp was still 156 F
• Drained first runnings

• Double batch sparged, roughly 2.5 gal for each, at 170 F.  Stirred each and then drained almost immediately.  I tilted the mash tun this time to increase the amount of wort collected.  I don't have a barb or tube on my mash tun (as shown in the picture above) so the wort falls about a foot into the brew kettle when draining.  This results in a lot of splashing of the wort.  I am concerned that this will lead to some off flavors due to hot side aeration.  Hopefully the boil reduced the amount of oxygen in the wort.
• Added calcium chloride to the kettle
• Brought kettle up to a boil - I think I had about 7.5 gal at that point (would be nice to have a sight-glass) - took about 20 min
• Added hops at the start of the 60 min boil

• Re-hydrated the dry yeast after 30 min of the boil
• Added irish moss for the last 20 min of the boil
• Put the wort chiller in the kettle to sanitize for the last 15 min

• Chilled wort - took 15 min to get to tap water temperature (80 F)
• Got a whirlpool going after removing the chiller and drained from the side - managed to leave behind a majority of the hops - Pretty good cold break on this one (Irish Moss worked for me) which I avoided transferring for the most part
• Mixed the yeast in at the start of the transfer
• Shook to aerate
• Put into 65 F fermentation chamber - due to larger than planned volume (5.5 gal) I decided to go with a blow off tube rather than normal airlock

• 4/14/14 - No bubbling yet but based on the carbon dioxide smell (burn) in the fermentation chamber that wasn't there yesterday I can tell there is some fairly active fermentation underway
• 4/16/14 - Three days in I took a gravity sample - we are now at 1.015 at 65 F - it was still bubbling away but the kroisen is gone.  I could taste the alcohol in the sample but it was still pretty sweet.  Color was basically black now that it's cleared up a bit.  I don't feel 100% comfortable opening the fermenter at this stage but I wanted a picture.

• 4/24/14 - Moved into the 80 F house while cold crashing my previous batch
• 4/26/14 - Moved back into the 64 F fermentation chamber
• 5/8/14 - Cold crashed down to 33 F
• 5/9/14 - Added gelatin for fining
• 5/10/14 - Bottled with 3.5 oz of priming sugar.  Ended up with 50 12 oz bottles.  Measured final gravity as 1.009 at 72 F.  Per my hydrometer calibration this is actually 5 point off so my actual FG is 1.014.  The sample tasted very good - it has a really nice chocolaty flavor with subtle sweetness.  Looking forward to this one conditioning up.
• 5/23/14 - First Tasting - A harsh alcohol flavor has taken center stage in this beer and it's made it difficult to drink at this point.  Decided to give it a couple months to mature a bit and do another tasting at that point to see if it has mellowed.  I'm not holding my breath.
• 6/21/14 - I have had a few more bottles since the initial tasting.  Some of the bottles have had the nice chocolaty and roasty flavor dominate as was the case in the tastings prior to bottling and some have still been dominated by alcohol.  The ones that tasted good had spent the last month in the refigerator rather than at room temperature - I wonder if that could be a factor.  I am feeling more optimistic that the beer was still green at the first tasting and that it will mature into a tasty beer.
• 7/15/14 - Second Tasting - The beer is much improved after two months of aging - the strong alcohol flavor has faded significantly.  It's a tasty beer but it doesn't have a whole lot going on besides a dry roast flavor.
• 9/11/14 - Drank my last bottle of oatmeal stout today.  This was probably the best bottle I'd had.  It was very smooth and dry but had a nice subtle roasty/chocolaty finish to it.  I didn't get any of the alcohol flavor that I got in earlier batches.

Lessons Learned:

1. My understanding of how to use a hydrometer was incorrect - I did not factor temperature of the sample into my initial readings unfortunately.  Next time I need to take that into account when taking my reading.
2. As stated above, I may be aerating the wort and causing off flavors when transferring from mash tun to boil kettle.  Only time will tell on this.  For my next batch I need to buy a hose barb and some rubber tubing so that avoid the possibility of hot side aeration and the associated oxidation off flavors
3. I think I got the water volume behavior of my system basically understood.  I used about 8.5 gal of water to get 5.5 gal of wort at the end of the boil.  It would be very nice to have a sight glass on my boil kettle so that I could have more specific measurements of my volumes.
4. I think I could save some time on my brew day with a larger HLT - using my 5 gal pot is okay but since I need 8 gal I end up having to heat up a couple patches of water for strike and sparge.
5. I came dangerously close to running out of propane before the boil was complete.  The burner was sputtering for the last 20 min of the boil (I suspect this was due to pressure reduction in the tank).  If I'd run out of gas it would have been a major inconvenience to go and get more.  A second tank would be a worth while purchase
6. My practice of pitching the yeast into the wort at ~80 F and then chilling down to fermentation temperature is not recommended by the yeast manufacturers and seems like a strong potential cause for the heavy alcohol off flavor in this batch.  Going forward I will not pitch the yeast this high to eliminate one possible cause for these off flavors.