Increased efficiency when increasing batch size?

[Babbage78]

Yesterday I brewed my first ever 10 gallon batch. I decided to make a cream ale just to keep it light and because I didn't really know how much grain and water my 10 gallon cooler mash-tun could handle. Here are the grains i used:

10 lbs golden promise
7 lbs six-row
2 lbs flaked corn
and a lb of corn sugar in the boil.

My batches usually end up somewhere around 70-72% efficiency when i make 5 gallon batches but yesterdays batch got me a whopping 85% efficiency. Now don't get me wrong, i'm okay with a bit more booze but I also like to have complete control over my process.

Here are a list of things I did differently than normal in yesterdays session that from when I normally brew. I'd love to hear your opinions on what might have increased my efficiency.

1. While I was mashing I had to run out and so the mash lasted about 2 hours at 154.

2. I also used a mashout to help divide my water additions to the mashtun.

3. I used corn sugar instead of table sugar.

4. I also threw out about a gallon of run off from my sparge, I'm not sure if that means my efficiency is actually lower or higher than i've already calculated.

 

[didinho]

1. While I was mashing I had to run out and so the mash lasted about 2 hours at 154.

I guess this is the point: you could change the title of the topic in ' Increased efficiency when increasing saccarification times' .
how long do you usually mash?

 

[Gavin C]

Generally the bigger the batch on the same system will increase your efficiency simply because all the constant volume losses remain the same so are a lower percentage of the batch size.

Kettle/chiller/hoses dead space remains the same

Mash tun dead sace remains the same

I don't believe it will acount for the jump from the 70's to the 80's you report but that depends on your volume losses.

Tossing the runnoff won't increase BH efficiency as that is solely determined by the sugars that made it to the FV and the maximum potential sugars available.

If you are tossing sugars that out will potentially reduce the efficiency. (It would have no effect if you were tossing them anyway whilst the sugar was still in the mash-tun)

 

[Babbage78]

Thanks for the replies! I was guessing that the most important factor was probably the mash time seeing as I usually mash for 60 mins, but I have mashed for 90 mins before and didn't see such an increase.

It's also good to know about the bigger batch efficiency.

I'm going to see if I can replicate this efficiency with my next batch by letting it mash for 2 hours again, as long as it doesn't hurt the beer.