Original gravity variation

[Kevin b]

hey all, I just brewed a batch yesterday and the estimated og was 1.073 and it came out to be 1.050 post boil. I know I can alter the numbers with dme but I’m curious why such a difference? Any input appreciated.

 

[JimRausch]

Extract or All grain batch? Need a few more details in order to help.
By the way- welcome to the forum!

 

[Kevin b]

Thanks, it’s all grain.
11lbs 2-row
1Lb red wheat
1lb flaked oats
.25 honey malt
.50 rice hulls

Thanks

 

[beer-me-now]

Looks like 1.073 OG was assuming 75% efficiency but in reality you only had 50% efficiency, meaning you didn't extract as much sugar out of the grain as you potentially could have. Next step is to post your full process and hopefully someone can point out ways to help you improve. I use brew in a bag method and my local shop doesn't mill the grains very well at all, I know this now and make necessary adjustments with more grain in the recipe. I regularly get 40 - 50% efficiency but don't mind paying a few extra dollars in grain to reach the gravity numbers I need.

 

[doug293cz]

What were your pre-boil and post boil volumes? Did you happen to get a pre-boil SG? Did you get a first runnings SG? Did you sparge? If so what was your sparge process, and what were the strike, and sparge volumes? These are all things you should keep track of, if you want to understand your efficiency (which you need to do if you want to be able to predict, and hit, target OG's.)

Brew on

 

[Kevin b]

I’ve been putting together an all grain system over the past year or so. I use a 5 gallon water dispenser I converted into a wort tun so in this batch I was only able to fit about 16qts of water in with the grains I let it sit for an hr at 152 deg I then sparged it at 170 to get 6 gallons pre boil with an hr boil I got Mabey a hair under 5 gallons into the fermenter. I’m using a gallon glass carboy for fermenting and it looks great and smells great hopefully this will still come out good

 

[Kevin b]

I think if my mashtun were a little bigger it might help out. Also now that it’s brought up I think my grains could be crushed a bit finer

 

[doug293cz]

I’ve been putting together an all grain system over the past year or so. I use a 5 gallon water dispenser I converted into a wort tun so in this batch I was only able to fit about 16qts of water in with the grains I let it sit for an hr at 152 deg I then sparged it at 170 to get 6 gallons pre boil with an hr boil I got Mabey a hair under 5 gallons into the fermenter. I’m using a gallon glass carboy for fermenting and it looks great and smells great hopefully this will still come out good

Fly sparge or batch sparge?

Brew on

 

[Kevin b]

Normally I try to fly sparge, but this time I batch sparged it’s the first time I’ve batch sparged

 

[doug293cz]

Ok, looking at your grain bill, and the volumes for a single batch sparge, if you had gotten 100% conversion efficiency, you lauter efficiency would have been about 80 - 81%, and so would your mash efficiency. Your OG would have been about 1.075. To get an OG of 1.050, your conversion efficiency would have to have been about 64%, lauter efficiency about 83% (lauter eff goes up a bit with more dilute wort), and mash efficiency of about 53%. The other possibility is that there was something terribly amiss with your batch sparge process. But, if you drained fully after the mash, and stirred your sparge water in well (5 min or more) it's unlikely that you would have lauter issues.

Needless to say, 64% is terrible conversion efficiency. A well done mash can get 95 - 100% conversion efficiency. Usually the biggest detractor to conversion efficiency is too coarse a crush, which leads to the conversion being incomplete after the allotted mash time. Things you can do to improve conversion efficiency:

• Crush the grain finer, especially with small kernel grains like wheat.
• Stir aggressively at dough in, and make sure you have no dough balls
• Mash longer
• Make sure your thermometer is calibrated, and your mash temp what you think it is.
• Adjust your water so that mash pH (measured at room temp) is close to 5.4

You can actually test your conversion efficiency during the mash using the method here.

Brew on

 

[Kevin b]

Thanks for the input I appreciate it. I’m going to pick up a grain mill I think the premilled grains I’ve been getting from homebrew.org are to course to get the most sugar extraction. Everything else I’m doing should be right on the money.

 

[dwhite60]

May be some homebrew stores set their mill for a coarse crush so you'll get low efficiency and thus buy MORE grain to make up for it next time?

All the Best,
D. White