Physics would disagree with you…lemme see if I can find the info…but the basic idea is that since you aren’t anywhere near the limit of solubility of sugar in water, there is no difference made by water temp. Kai has even demonstrated that cold sparging doesn 't reduce your efficiency.
Any increase in gravity is more likely from increased conversion due to hotter water, not better extraction. Keep in mind that in batch sparging you’re draining, not rinsing, the sugar from the grain.
Thats cool. Maybe lautering is an even better word than rinsing or draining. In any event, it wouldn’t be the first time that I’ve done something that physics or science disagreed with. [emoji85]
Solubility isn’t the only issue that sparge water temperature affects. Hotter water decreases viscosity as well. Even if no extra sugar is dissolved in the mash, you may end up with less stuck to the grain material using hotter sparge water.
I’ve never been able to find anything that points to that. I’m not even sure how the sugar could stick to the grain.
I’m not necessarily saying it’s true, but the homebrew lore I’ve always heard is that by raising the temp of the grain bed you allow the liquid to flow more freely and therefore drain better. I’m not saying that the sugar itself is stuck to the grain, but the sweet wort is held in it like a sponge. Sort of like if you had a grain bed saturated with honey or molasses, just at a more dilute scale. The warmer the sugar solution is, the lower its viscosity (you can plot a curve of temp vs viscosity for a sugar solution at a given concentration), and the more freely it will flow.
Of course, now that I’ve talked it out, that doesn’t really seem to make much sense as far as batch sparging is concerned. Viscosity would only have an effect if it prevents you from draining the full volume you are shooting for. If you’re hitting your volumes, then viscosity isn’t having an effect.
Here’s another thought on why Jim may have seen a difference between the two sparge temps. Imagine if you have two identical sponges that are saturated with sugar solution. Toss one in a gallon of cold water and another in a gallon of hot water. With enough time and mixing, both solutions will end up at the same equilibrium concentration. But the hot water will tend to get there first.
A cold water batch sparge should net you the same extract if given enough time. But the sugars will dilute into the sparge water faster in a hot sparge. If you run off before your sparge water hits equilibrium sugar concentration with the grain material, then you would net less extract.
Well the sugar must be on the grain, where else could it be? So you mash, then drain, and between draining and adding your sparge water, the remaining sugars are on the grain, in the grain, on the walls of the mash tun… now add sparge water. Where’s the sugar? I’d guess its being absorbed by the water, and my money would be on that happening more efficiently the hotter the water is. However, its just a hunch and I can’t prove it. Even the difference in my recent little test isnt proof. It may or may not be evidence, but not case closed.
In the end, if your ph is right, I beleive 170, 180, 190, all good. Even 212 probably.
I batch sparge and heat the second (last) water addition to about 185. This gets the grain bed to about 168. I’ve had good results with this method from both a taste and efficiency perspective (usually around 80% extraction efficiency).
Yeah, that’s the lore, which is why I’ve researched it. Not so according to physics. I’ve also experimented with cold sparging and it doesn’t take additional tome to get the same extract. I’ve become convinced that the benefit of hotter sparge water is better conversion efficiency.
The sugar is in the liquid, not the grain. Jim, try cold sparging. I have, as an experiment. No difference assuming you have 100% conversion efficiency first. That’s the key…check you conversion efficiency.
I do. I use Kai’s chart of gravity per qt/lb. I dont doubt that cold water works, but I’ll stick with 170-190 since it also works and it has to get heated eventually.
Back to sugars in liquid not grain. What I mean to say is that the sugar is in the grain bed… its in the grain bed, right? And what you are saying is that in the wet grain bed, its in the wet, not the grain.
Scientifically, when at time zero two miscible liquids are combined with different concentrations of a solute, over time the solute will travel from an area of higher concentration to that of lower concentration until equilibrium is achieved.
In other words, the sugar is everywhere. Inside, outside, USA.
I do a fast fly sparge/batch sparge with 165 degree sparge water. I heat my mash up to about 160 or so by recirculating (manually with a small pot) my mash wort … direct fired mash tun. I would say I recirculate for about 5 minutes to clear and heat the mash to 160ish. I then sparge (via “sparge ring”) and stir the top 1/2 of the grain bed and collect about 8 gallons of wort in about 10 minutes… maybe 15 minutes tops. The sparge never gets over 165 or so. The grain bed never gets over 165. I routinely get about 83-87% efficiency. I start heating my boil kettle as soon as the bottom is covered with wort. I would say from the time my 60 minute mash is done, until I have collected 8 gallons of wort is about 15 minutes, tops.