Improving Brewhouse Efficiency
The term Brewhouse efficiency is used to describe the percentage of sugars that you are able to convert and extract from the grains. As all brewers and brewing systems are different, this percentage can vary greatly. While there is always going to be some loss, with a few simple adjustments you may be able to increase your overall efficiency.
Learning your brewhouse efficiency is very important when creating a recipe, as without it you would never be able to accurately determine your estimated original gravity. For example, most recipes that you find in books will calculate your estimated efficiency at 70-75%. But if you are actually only extracting 60% of the potential sugars then you will alway be short of the estimated gravity or find yourself making adjustments to the recipe to account for this loss. What can you do to improve your efficiency?
The first thing to look it, is how fine your grains is being crushed. This can substantially affect your overall efficiency. It is important that the grain is being finely crushed, but not so much that the husks are destroyed. An intact husk is needed as to work as a filter and will keep the grain from compacting so much that you get a stuck mash. Mills with 2 or more rollers are ideal as they are far more consistent at maintaining a good crush without destroying and shredding the husks. When using grains with little or no husk, you should always add rice hulls to replace the husks and to help keep you mash loose.
The next thing to look at is your mashout. As we all know, sugars are very sticky. A mashout is used to heat the overall temperature of the mash to around 168°F. This will effectively loosen the sugar so that it can be drained easily during sparging. Dependent upon your system, this may involve adding very hot water (over 200°F) to increase the grain bed to the desired temperature. Other system may involve directly heating the mash while re-circulating your wort. I find that many new all grain brewers skip this important step and jump right to sparging. In my experience, sparging alone does not increase the overall temperature enough to loosen all of the sugar from the grain. (It is important not to go over 170°F as you risk possibly extracting tannins from the husks.)
Now that the mashout has been completed, we need to sparge. When fly sparging, you want to continually add water around 170°F to rinse out the grain bed while draining at the same rate. This should be be done very very slowly. I usually recommend sparging at approximately 1 quart of wort per minute. Many new brewers try to rush through sparging leaving valuable sugars behind. (You want to stop sparging prior to reaching a gravity of 1.008 so you do not extract tannins.)
Mash Tun and System Loss
The last and one of the most overlooked ways to improve your brewhouse efficiency comes down to your system itself. In your mash tun, when using a false bottom that does not have a dip tube, it is important to account for any dead space underneath the false bottom. You should also look at all aspects of your system as any wort that remains stuck in tubing, pumps, etc will also slightly reduce your over Brewhouse efficiency. These are all very easy things to fix and together can make quite a bit of difference
If you have any other questions regarding calculating or improving the efficiency of your brewhouse, the staff at The Brew Hut will be happy to help.