When I was designing my new brewery, I wanted to come up with something that would allow me to produce beers quickly and consistently. One time/space/money saving measure I took was to do without sparging.
By foregoing a step of the traditional brewing process I would not require a hot liquor tank or any of the associated plumbing. Seeing as I definitely wanted to use sanitary triclamp fittings throughout, and they’re kind of pricey, a reduction in complexity of the brewery’s plumbing carried a fair amount of weight in my decision making process. While I was concerned about efficiency, both my budget and my desire to have shorter brew days were more important to me.
The efficiency concern
On my previous system I was getting brewhouse efficiency that was in the mid 80s with a single batch sparge. With my new system, I was prepared for values 10-15% lower.
You can think of grain as sponge, it absorbs something like 0.12 gallons of liquid per pound. After the mash, the sparge partially recovers some of the sugary liquid retained by the grain by rinsing it with water. Without the sparge, these sugars travel with the grain to the compost bin.
Whether you sparge or not, the same amount of water is required to reach the pre boil volume. So, while BIABers do not sparge, for instance, they use a very thin mash to achieve proper pre boil volumes. This in effect extracts a fair portion of the available sugars. In my case, the liquid in the mash is divided into two vessels such that I have traditional mash consistency in the mash lauter tun (allowing a nice grain bed to form), and all of the “extra” in the boil kettle (in direct contact with a heating element). As I recirculate during the mash, I am able to maintain or ramp mash temperatures with setup.
Brewhouse efficiency is measured as the percentage of the total sugars contained in the grain that make it into the fermenter. I’ve always been skeptical when I heard of BIABers getting efficiency numbers in the 80s. I’ve ran the numbers, and it’s not entirely impossible. To obtain 80%+ efficiency with a no sparge system you must achieve excellent conversion with very low grain absorption. This can be done by having a very fine crush, good temperature control, and compressing liquid out of the grain bed.
It turns out efficiency decreases roughly linearly with grain bill size. I created a shiny app to calculate brew house efficiency for no sparge breweries across a range of typical grain bill sizes. The app also provides a linear equation that allows you to estimate brewhouse efficiency very closely on future recipes.
It turns out for my new system my brewhouse efficiency will be around 70-76%, assuming 95% conversion efficiency. So, I was close in my estimation of losing 10-15% off my previous system. I’m happy with this, and I think I should be able hit my numbers very consistently using the linear equation I’ve generated with this app.
If you’re interested in the code, it is hosted on github.