1st Batch Sparge; Low Gravity

I did my first batch sparge yesterday and, while the procedure went well, I felt that I might have done something wrong. My efficiency was very low and ended up with a lower than expected OG. Here's a quick step by step:

12 - lbs pilsen 2 row
2 - lbs white wheat
1/2 - lbs munich
1/2 - flaked oats

4.7 gallons of water @172 degrees stabilized mash @152 for 70 minutes.
Drain first runnings.
4 gallons of water @185 degrees for mash-out @168 for 10 minutes.
Drain second runnings.
Collected 7.25 gallons in kettle.
add 1 - lbs honey.
Boil for 65 minutes, chill.
collected 5.25 gallons.
Original gravity was 1.070.

I thought I would be more around 1.078 with 15 pounds of grain and 1 pound of honey. Where did I go wrong? Or is that to be expected with batch sparging?

Thanks!
-Mike

How much wort was left in the bottom of the boil kettle after you collected the 5.25 gallons into your fermenter? It's possible your water volumes may be slightly off, as boiling 2 full gallons off during a 65 minute boil sounds like it might be a tad bit high, unless you had a super vigorous boil the whole time.

ziggy13 said:

How much wort was left in the bottom of the boil kettle after you collected the 5.25 gallons into your fermenter? It's possible your water volumes may be slightly off, as boiling 2 full gallons off during a 65 minute boil sounds like it might be a tad bit high, unless you had a super vigorous boil the whole time.

Click to expand...

My kettle valve does sit a little high from the bottom. Probably 1/2 gallon of wort was left behind.

That would account for some decrease in efficiency...do you have a sight gauge or how were you measuring volumes?

ziggy13 said:

That would account for some decrease in efficiency...do you have a sight gauge or how were you measuring volumes?

Click to expand...

I have incremental marks on my kettle and I use a gallon bucket to measure from out of my mash-tun.

Do you think my OG was way off, or just off by a little?

Thanks for the replies!

-Mike

There is a nice all grain calculator here: http://www.brewersfriend.com/allgrain-ogfg/

According to it, it would seem you have about a 64% efficiency. Not great, but I wouldn't say it's terrible for your first time. Was this your first all grain batch or just your first batch sparge?

First batch sparge. Also my first batch in over 8 years! I was an avid homebrewer back in the late 90's. I just recently got back into it.

I'm sure the beer will be great! Maybe a tad low but nothing to worry about! Welcome back to the hobby.

Did you stir in the sparge water when you added it? For a batch sparge to be efficient, you need to stir each batch of sparge water really well as it is the stirring that causes most of the sugars to be dissolved.

-a.

ajf said:

Did you stir in the sparge water when you added it? For a batch sparge to be efficient, you need to stir each batch of sparge water really well as it is the stirring that causes most of the sugars to be dissolved.

-a.

Click to expand...

A little, but not much.

Thanks!

The low-ish efficiency might have to do with volumes, as mentioned above. Another option is grain crush. For me, when I began crushing my own grain, I saw about a 15 point jump in efficiency. Many here have the same experience.

That being said, the key issue to hitting your target gravity isn't really raising your efficiency but being able to accurately predict your efficiency. If you know that your efficiency is 60% or 70% or 80%, you can build your recipe to hit your target efficiency.

For example, I have my system/process dialed in at 70% percent efficiency. I seldom miss my target gravity by more than a point or two.

Hope this helps, and welcome back to brewing.

LaFinDuMonde said:

A little, but not much.

Thanks!

Click to expand...

Thats your issue. Batch sparging rinses the grains mostly only when you stir. I make it a point to stir for like five minutes after adding the sparge water.

Also , palmer wrote about how the lauter tun filters being important to how you sparge. If I remember correctly, false bottoms and most manifolds work most efficiently with fly sparging, and ss braids work most efficiently with batch sparging. Of course, at my age, "if I remember correctly" should be taken with a grain of salt

Stirring the sparge water for 5 min. is a bit excessive, IMO...a couple min. should be more that enough.

False bottoms and manifolds work fine for batch sparging and braid is fine for fly sparging if it's configured properly. It's the design, not the material, that makes the difference.