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-   -   Fly sparge vs. batch sparge in terms of solubility (http://www.homebrewtalk.com/f128/fly-sparge-vs-batch-sparge-terms-solubility-230527/)

 jaketothemax1000 03-07-2011 07:53 PM

Fly sparge vs. batch sparge in terms of solubility

I keep reading that higher extraction efficiencies are more attainable with a fly sparge than with a batch sparge. I'm having trouble conceptualizing what would account for the difference in solubility of the sugars between the two methods. It seems to me that the sugar is going to have a given Ksp at a given temperature and once it reaches saturation it will stop dissolving. Therefore the same amount of water will be able to hold the same amount of sugar in solution no matter if it is added in increments(as with a batch sparge) or continuously(as with a fly sparge). Can anyone shed some light on this?

 MalFet 03-07-2011 08:04 PM

It has nothing to do with solubility. The difference in theoretical sparging limits between fly and batch systems is a consequence of sugar concentration equilibriums between the water drained from your tun and water absorbed by the grain. Gradual rinsing ends up being slightly more effective at dropping those equilibriums than batch rinsing. Braukaiser.com has some good explanations of this stuff.

 TheSeether 03-07-2011 08:06 PM

I am far from expert on this and my analogy is going to be so rough it is laughable but mull it over for a second.

Imagine a clod of mud dried to the bumper of a car. This is your sugar. Now, for a given volume of water which method below would remove the most mud from the bumper?

1) Dunk the bumper in a vat of water, swish it around and remove to dry.

2) Slowly pour the vat of water in a localized stream over the clod of mud until the water is exhausted (catching the resulting stream in another container).

The argument considers the volume of water to be sufficient to dissolve and contain all of the mud should it come off the bumper. However, one method is going to get more of the mud off the bumper and into the water over the other method, for sure. Also, the possibility exists that both methods will get the same amount of mud off of the bumper.

Scientific enough for you?

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