Drop in efficiency - too much specialty grain?

Hi All.

I recently brewed a beligan dubble using Deathbrewer's all grain stove top method.

Here is the recipe: 3.25 gallon

2800g pilsner
300g special b
250g caramunich
200g aromatic

450g dark candi syrup
hallertau and magnum hops

This brew only gave me 64% efficiency. The previous batch I did was a chimey bleu clone. Same ingredients though different quantities. More pilsner and much less speciality grain. With that recipe I got about 73% efficiency.

Could my drop in efficiency be due to using too much speciality grain with respect to base malt? My process was exactly the same and I was careful to keep the mash temp constant. No dough balls in mash either.
Next time should I decrease the speciality malts? Will my efficiency then increase?

Cheers, Andrew.

Your specialty grains are only 22% of the mash, so I don't think that's your problem.

How long was your mash?

I mashed for 90 mins. Temp was pretty constant throughout.

Sometimes my effeciency will decrease with an increase in grain. Did you mill your own grain?

There was actually more total grain in this recipe than in my previous one.

I didn't mill the grain myself. I was using up the leftover speciality grians from my first batch. The speciality grains would have been a 2 - 3 months old. Could this have caused the efficiency drop? Though I have kept them in an airtight bag in a cool dark place (my garage). The pilsner was fresh and from the same place as the pilsner used in the first recipe.

Did you get an OG of 1.067 for your 3.25 gallons?

I got 1.066 after measuring just before I pitched the yeast.

So what was different between the two batches?

I try to keep everything as consistant as possible. Here's is what I'll call my zero, my reference point and the parameters. Also, all the same equipment each time.

Single Infusion
8 lb grain bill
Mill is set where it's been for several years
Strike water to grain ratio 1.25 qts : 1#
Mash temp 154 degrees for 60 minutes
Sparge water to grain ratio 2 qts : 1# @ 175 degrees
Boil 1 hour
Final volume 5.5 gallons
OG 1.048-1.050

Well the only difference between the two batches was the grain bill. Strike water temp was the same. I mashed both at 152 F using 1.25 qts/lb of water. Both were 3.25 gallon recipes.

grain bill for new recipe was

2800g pilsner
300g special b
250g caramunich
200g aromatic

grain bill for old recipe was

3915g pilsner
147g caramunich
112g aromatic
73g special b
44g chocolate

For both recipes I used the batch sparge technique. Basically I dumped the drained grains into the required amount of water to produce a final boiling volume of 3.99 Gallons. The amount of sparge water required for each recipe was not the same due to the total weight of the grain bill being different and therefore the amount of stike water and water absorption being different. I sparged at 172F I think for each recipe. Both temps were the same.

I think it is your mash pH. You'll have to change your water along with adding more dark malts to the grist. If not, the acidic dark malts lower the pH too much and the enzymes won't be as effective. Do you have a water report for your water?

Kai

One thing is, I don't think the percentage of speciality malt had anything to do with it.

I really wouldn't get stuck on what happened. Is it possible it's not that you did anything different but what you did doesn't give consistant results? I think it's a possibility. If you really want to dial in your efficiency, come up with your point of reference and wear it out until you get the same results every time.

The water I used was Tesco's mineral water. Here's the info on it

Here is the details... all in mg/litre

Calcium 10.0,
Magnesium 2.5,
Sodium 9.0,
Potassium 2.0,
Bicarbonate 25.0,
Chloride 12.0,
Sulphate 10.0,
Nitrate 11.0,

pH at source 6.2

Is there any way using beersmith etc that you can calculate how the mash ingredients will effect the ph of the water you are using so as you can compensate with brewing salts etc more accurately than just changing the ph of the water pre mash.

It should be noted that I used the same water for each recipe

You have very soft water and all that dark crystal dropped your mash pH substantially. As a start I'd add 0.4 g baking soda and 0.8g chalk per gallon of strike water.

But in gerneral you'll have to adjust your water chemistry to match the acidity of the grist. The latter is largely determined by the use of dark malts. While there are exeptions, you can say that the darker the beer the more alkaline the water has to be. You can get this alkalinity from baking soda and chalk. baking soda dissolves better but raises the sodium level while chalk doesn't dissolve well but is limited in its ability to raise the pH (at least when not dissolved by CO2).

Because of your soft water I recommend that you start looking into water chemistry. It's a tough subject but give it a try. After reading it from many sources you should have good idea of what is going on.

Kai