I have an odd urge to contribute to everyone's theoretical understanding of brewing. We can all improve our methods by living by the motto "There are no black-boxes," meaning we shouldn't just go through the motions without understanding what we're doing or why. That leads to silly superstitions and flat-out incorrect methodology at times.
I've noticed that a good number of you have experimentally observed the efficiency difference between single and double sparge methods when brewing. Generally, you will find that double sparging leads to greater efficiency. As a chemist with a strong analytical background I often take the mathematics of this phenomenon for granted. Some of you may be interested in seeing why exactly a greater number of small-volume batches result in greater extraction.
Before linking to the math, this is the basic situation. Regardless of whether you are rinsing out a glass or sparging grain, two small rinses of say 5 mL (arbitrary volume) will always extract more than a single rinse of 10 mL even though you used the same total volume or rinse water. If you need proof, check out this relatively well written chemistry lab I found online:
http://www.ic.sunysb.edu/Class/che133/techniques/rinsing/rinsing.html
If someone needs simplification or wants to see this math applied to brewing directly, let me know. If I don't check back, I know there's someone else lurking here that could step up!
Happy brewing, friends.
I've noticed that a good number of you have experimentally observed the efficiency difference between single and double sparge methods when brewing. Generally, you will find that double sparging leads to greater efficiency. As a chemist with a strong analytical background I often take the mathematics of this phenomenon for granted. Some of you may be interested in seeing why exactly a greater number of small-volume batches result in greater extraction.
Before linking to the math, this is the basic situation. Regardless of whether you are rinsing out a glass or sparging grain, two small rinses of say 5 mL (arbitrary volume) will always extract more than a single rinse of 10 mL even though you used the same total volume or rinse water. If you need proof, check out this relatively well written chemistry lab I found online:
http://www.ic.sunysb.edu/Class/che133/techniques/rinsing/rinsing.html
If someone needs simplification or wants to see this math applied to brewing directly, let me know. If I don't check back, I know there's someone else lurking here that could step up!
Happy brewing, friends.