Extract Steeping Efficiency - Higher OG than Expected.
I brewed an extract batch yesterday (my fourth) for a Porter. This recipe used a pretty large amount of steeping grains for an extract batch (4.375 lb)
I steeped the grains for about an hour in 155-160F in two gallons of water. Then I rinsed them through a colander with another gallon of hot water.
I've been using BrewersFriend to do my calculations. For extract batches it uses an efficiency applied to the steeping grains only. It recommends using 30%. I though I might do a little better but looks like I might have done a lot better. I was expecting an OG of 1.075 -1.080 I got ~1.090. From brewers friend here are a few values of efficiency and OG:
30% - 1.072
50% - 1.078
70% - 1.083
90% - 1.089
Anybody seen this before? This effect probably shows up more on this batch because I have so much steeping grain. My last batch only had 1 lb and I hit OG dead on.
This batch used:
6.6 lb - Liquid Malt Extract - Light (50.9%)
1 lb - Dry Malt Extract - Light - (late addition) (7.7%)
1 lb - Dry Malt Extract - Light (7.7%)
1.5 lb - American - Munich - Dark 20L (11.6%)
0.5 lb - American - Caramel / Crystal 80L (3.9%)
0.5 lb - American - Caramel / Crystal 120L (3.9%)
0.625 lb - American - Chocolate (4.8%)
0.25 lb - American - Wheat (1.9%)
0.5 lb - Flaked Oats (3.9%)
0.5 lb - American - Pale 2-Row (3.9%)
I had a similar issue recently with a light lager I did. The 2-row and possibly the wheat (if it was wheat malt) likely converted the other malts while you were steeping. If you change your type to Partial Mash (from Extract, I'm assuming) on BrewersFriend, does it fall more in line with the OG number you got?
Congratulations on your first partial mash!
The extract will give you an OG of 1.065 in 5 gallons.
4.375 lbs of grain at 75% mash efficiency will give you an additional 23 points or a total of 1.088.
You mashed! 4.375 lbs in 2 gallons is slightly less than 2 quarts per lb (normal mash is about 1 to 1.5 quarts per lb). The 2-row and the Munich would have provided the enzymes to convert the starches.
For reference, if you do truly steep (lots of water, and very little grain), 2-row, wheat, oats, and Munich will give you 0% efficiency. So either you mashed, or your reading is way off.
Actually a partial mash was kinda what I was thinking. The recipe I started from called for the 1.5 of munich. From what I've read Munich needs to be mashed but is borderline for having enough enzymes (Diastatic power?). So I added the two row.
I'll mess around with brewers friend in pm mode. I was using extract before.
I tried pm mode in brewers friend and got he same results. I messed around a little and figured out what math it is doing....
OG is the sum of this for all ingredients
Efficiency is always 100% for extract
Sounds like this method may not be correct for true steeping with Munich. Is it possible that my rinse/spare process is just really efficient? I did use a full gallon of hot rinse water, then collected drippings from the grains.
The way I've heard it is if you use a weighted average of the diastatic power for all of your grains and have around 35 degrees Lintner / Lb or more it will convert.
So on yours:
.25*145= 36.25---------Wheat Malt
1.5*25= 37.5-----------Munich 20L
143.75 deg.L / 4.375 Lbs = 32.9 deg.L/Lb
So you're right around that mark and with a mash of 1.83:1 water to grist ratio for 1 hour as well as the good rinse you gave it you probably got a very sugary wort.
Time is also a factor (the longer the more conversion). The OP 'steeped' for an hour at 2 quarts to a lb. Most people use 1 to 1.5 quarts to a lb (thicker mash), and conversion is usually done in about 20 to 30 minutes.
If he had only 1 or 2 lbs in 2 gallons, he would have likely gotten a lot less conversion.
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