Low efficiency

[chrispy321]

Hi guys. I am quite new to all grain brewing, my 6th attempt tastes and smells great, but I used 6.5kg grain for 5 gallon brew and only had 4.2% alc. (1040 og - 1008 fg ) I guess its to do with my mashing - im using a converted cooler box at 65°c. Any advice would be appreciated please.

 

[Gnomebrewer]

That's really low efficiency - somewhere around 40%. The most common culprit is a poor crush (especially if there are un-cracked kernels); if you have whole kernels, you need to crush finer (are you crushing yourself, or buying grain already cracked?).
To be sure where the problem is (if grain crush is ruled out) you need to take some measurements. Measure the gravity of the wort during the mash. Measure the gravity and volume of wort into the kettle. Measure the final gravity and volume of wort. That way you can determine where the problem lies.

 

[chrispy321]

Ok thanks a lot, il start looking at it - I buy the grain on line crushed.

 

[Gnomebrewer]

Do you have a photo of some of your crushed grain?

 

[chrispy321]

I have the spent grain in a bag - is that any good

 

[Gnomebrewer]

Not really. Check the crush for the next batch before you brew - if there are many untracked grains, ask for it to be crushed finer.

 

[BrewnWKopperKat]

http://braukaiser.com/wiki/index.php/CrushEval ?

 

[GBRbrew]

What kind of water are you using? I just made the change from using my tap water to ro water and my efficiency jumped 10 points from 65% to 75%

 

[chrispy321]

Tap water I have been using and funnily enough I was previously having different problems so changed to bottled as a one off - and it was significantly more efficient ( in hind site )