Today I brewed this oatmeal stout:
Oatmeal Stout
5 gallons, all-grain
OG = 1.052 IBU = 35
The recipe specifies about 10 percent oats, for which a single-step infusion mash will suffice.
Ingredients:
8 lbs. pale two-row English ale malt
1 lb. crystal malt, 60¡ Lovibond
18 oz. oatmeal (quick)
0.5 lb. chocolate malt
0.5 lb. roasted barley
1/2 tsp. Irish moss
2 oz. Fuggles hops for boiling (4.2% alpha acid), for 45 min.
1 pack Wyeast 1084, Irish ale yeast
Step by Step:
Prepare a yeast starter a day or two before you start your brewing. Mix the crushed grains well in a clean, dry bucket. Heat 11 qts. of water to 174¡ F. Mash in slowly in stages, as described below. The temperature of the mash should be between 150¡ and 158¡ F. Within this range, higher levels give a less fermentable wort and a more full-bodied beer. Lower temperatures give a more fermentable wort. Acidify 5 gals. of sparge water to a pH of 5.7 using lactic acid. Homebrewing shops sell solutions of 88 percent lactic acid concentration. A stock solution of the acid may be prepared by mixing 2 tsp. into 3 cups of water. This stock solution can be stored, and using about 1/2 cup will reduce the pH of 5 gals. of tap water to nearly 5.7. Be sure to verify this using pH papers or some other means. Acidification prevents excessive extraction of husk tannins. Heat the acidified sparge water to a temperature at or just below 170¡ F. Maintain the mash vessel at temperature for at least 1 hour. Mash out, raising the temperature of the mash to 168¡ F. To begin the sparge, slowly drain and collect 1/2 gal. wort from the lauter tun, then gently pour this back on top of the grain bed. Repeat twice more; this establishes the grain bed and produces relatively clear initial runnings of wort by filtering out any fine grain particles within the bed. Begin the sparge, maintaining the sparge water at or just below 170¡ F. Typically sparging for this recipes takes 45 min. to 1 hour. More time is needed if the oat content is increased. Collect 6.5 gals. of wort.
Boil the wort vigorously for 15 min. Add hops and boil 30 more min. Add Irish moss and boil 15 more minutes. Total boil is 60 min. Cool the wort to room temperature within 30 min. of the end of the boil. Siphon the wort off the trub into a sanitized fermenter. Aerate the wort for 15 min. Pitch the yeast starter. Seal the fermenter with an air lock, and let the fermentation proceed until complete.
Notes:
I bought lactic acid and a pH test to acidify the sparge water. I couldn't get meaningful or consistent results with the pH test, so I abandoned this step, and left the sparge water as it was.
Mash temperature was a bit to high - perhaps 168degF.
I bought an iodine starch test kit. This gave clear indications of remaining starch - much better than the pH test.
I fixed the plumbing on the cooler mash tun. It now has a better valve that gives godd flow control. The mashing and sparging processes went without a hitch. I collected 6.5 gallons of wort. I boiled the first 4.5 gallons in the 6 gallon pot and the last 2 gallons in the stock pot. The big pot got all the the hop additions, and so was boiled for the full hour. I boiled the small pot for 20 minutes, with no hops.
After cooling, I syphoned the wort off both pots into a bucket, so as not to disturb the trub bed. This made a big difference in the amount of solids going into the carboy.
OG was 1050. I bit lower than the recipe. This is probably because of the high mash temp.
I impovised an aeration tecnique. The the wort in the bucket on the counter top, and the carboy on the floor, I put the strainer funnel in the carboy, then piped the wort in the the funnel. I took an old bottling wand, and took out the valve plunger, and plugged the wand in the end of the pipe. The wand randomly sprayed wort into the funnel. I think this picked up a good amount of aeration.
