more help with efficiency

I finally did my first partial mash on the weekend. I mashed 2kg of grain with 5.6L and batch sparged with another 4.4 to yield about 8L of wort.

The grain bill was;
0.90 kg       Munich, Light (Joe White) (5.0 EBC)      
0.60 kg       Wheat Malt (Barrett Burston) (3.0 EBC)        
0.45 kg       Caramel/Crystal Malt -120L (236.4 EBC)        
0.05 kg       Chocolate Malt (Joe White) (900.0 EBC)

The OG into the kettle was 1.037 which i think equates with an efficiency of only 50%.

Can someone check this for me please?

As I used extract in the recipe, beersmith doesn't seem to be able to work on just the partial mash. I ticked the box that says "Add After Boil" but I still get 0% extraction efficiency into the boil using the "Brewhouse Efficiency" function.

Can you provide the entire recipe including the extract, that will allow us to better guide our answers.

Fred

Forgive the delay, fellas, been away from the computer, but here's the recipe.

1.50 kg       Coopers Extract -  Light Malt  (5.9 EBC)  Extract      27.5 %        
1.50 kg       Coopers Extract -  Wheat Malt (7.9 EBC)   Extract      27.5 %        
0.90 kg       Munich, Light (Joe White) (5.0 EBC)       Grain        16.5 %        
0.60 kg       Wheat Malt (Barrett Burston) (3.0 EBC)    Grain        11.0 %        
0.45 kg       Caramel/Crystal Malt -120L (236.4 EBC)    Grain        8.3 %        
0.05 kg       Chocolate Malt (Joe White) (900.0 EBC)    Grain        0.9 %        
35.00 gm      Saaz [4.00%]  (60 min)                    Hops         15.5 IBU      
25.00 gm      Saaz [4.00%]  (30 min)                    Hops         8.5 IBU      
1.00 tsp      Irish Moss (Boil 10.0 min)                Misc                      
0.45 kg       Dextrose (0.0 EBC)                        Sugar        8.3 %        
1 Pkgs        SafAle German Ale (DCL Yeast #K-97)       Yeast-Ale  

Batch Size: 23 L
Boil Volume: 8L

The expected O.G. is 1.060 with a measured O.G. of 1.048. As i said originally though, the S.G. of the 8L of wort from the grain was 1.037.

My guess is that the efficiency of the mash was 50%, which is probably less worrying than missing the overall O.G. by 12 points.

It's got me buggered, that's for sure.

Looking at your numbers and recipe your calcs are right on.  

Your mash efficiency was 50%.  Partial mashes are less efficient than full mashes.  A rule of thumb I've seen is to reduce efficiency by 30%.

I can't comment on your mashing technique since you didn't post it.

Try this add 1 to 1.3 qts per pound (metric equivalent) water to your crushed grain, hold at 150df (plus or minus) for one hour,  drain all water from the grain,  see how much water you need to hit your boil volume (don't forget the extract you are adding) and add that much water (approx 170df) back to the grain, stir and let sit for 15 minutes, then drain this into your kettle.  If you have a lot of sediment (from the grain) run the wort thru a strainer to clear.  

brew as normal.

Fred

Let me add that any efficiency number you get from partial mash might not be fairly representative of your technique.  This is because the program needs to calculate the efficiency from the overall SG and FG which includes the extracts you used in your brew.

In many cases the larger contribution to gravity from the extracts can mask out the smaller contributions of the partial mash grains.  Since there is variation in the gravity of the extracts, it can have a significant effect on the calculated efficiency from your mash.

In any case, don't worry as the beer itself will probably be fine.  Your techniques will improve over time and you will likely get much closer in later batches.

Cheers!
Brad

Fred

I ended up mashing in a foam esky and ladled the wort through a sieve into a pot. I mashed at a bit under the 1 quart per pound ratio and batch sparged to hit the boil volume. I would have let the sparge water sit for about 15 minutes and ladled through the sieve as before.

The wort was far from clear so i hope i didn't extract to many tannins. I racked the beer last night and the trub was right up to the tap!

Thanks for your help, fellas. I think it's time to get started on a decent tun!

Cheers

Barge,
 I recommend a plastic water cooler - they work great and are easy to use.  I have one with a "Phils false bottom" screen in it and it could not be easier to do an infusion mash.

Brad

Thanks Brad,

I'm going to look around and see what i can get at the right price. I definitely like the look of the coolers, but if i can get a cheap esky i'll go with that. i've seen some pictures on the net with these set up with braided stainless steel hose as the screen. They're probably not as efficient but look cheap and easy.

Barge.

A couple of weeks ago I got a 26L Red Cooper Beverage Cooler on special from CampMart at Capalaba for $39.90.

I use a stainless steel hose instead of a false bottom and achieved 75% efficiency with my first AG using continuous sparge.