the only time youre going to stir your grains is at dough in. you want the sugars to pool at the bottom of your tun, then fly sparge slowly to pool fresh water on top of the grist to push down the sugar into the false bottom and out into your kettle. this is the fly sparge method. ive heard of stirring the grist during a batch sparge, but ive never batch sparged and i usually get about 85% efficiency with fly sparging. there are people that claim 85% with a batch sparge, but the way my brain is wired, i dont see how it works. you also need to have proper mashing technique to get a high efficiency. thich mashes cause low efficiency, short mashes cause low efficiency, not protein resting with unmodified grains such as adjuncts and high 6-row content cause low efficiency. theres more to it. but as far as sparging, ive always had great results with the fly sparge method. and you never stir the grist with a fly sparge method.
Right, if you're going to FLY sparge, you don't stir after your first vorlauf. If you batch sparge, you stir very well after each batch infusion of sparge water. In fact, if you don't stir, it would be considered horrible technique.
"...claim 85% with a batch sparge, but the way my brain is wired, i dont see how it works"
Batch sparging works via diffusion where large concentrations of sugar in one liquid (sticking to the grains) will move to liquids of low concentration until it reaches equilibrium. Most of the sugar is drained from the tun before any sparging takes place.
It sounds like you are suggesting that people claiming to achieve 85% or better by batch sparging are either mistaken or lying. I can assure you that there are easily 100 regulars here that know how to measure and calculate efficiency, batch sparge, and regularly get 85%. It must be a conspiracy all led by Denny Conn.
well i wasnt suggesting that people are lying or mistaken at all, i simply meant i dont understand how a batch sparge works to achieve that efficiency. dont assume anything. i was very specific with my words, you might want to read that again.
well as far as fly sparging is concerned, i can tell you how to make that work, but like i said, i have no experience with a batch sparge, so you might talk to bobby m about that. he seems to know about it.
When fly sparging you want to do some recirculation before you start, just to get your grain bed to settle a bit and clear some of the sediment and bits of grist. Then you start to add water to the mash and drain it out at of the mash tun at an equal rate (I think about 1 qt a minute is correct or sufficient), and keeping the water about an inch above the top of the grain. Do don't stir using this method because the constant movement of water in/out from top to bottom removes the sugars from the mash evenly (this also depends on your mash tun setup). Stirring disturbs the grain bed. This is my best understanding, though I know some drain the wort from their tuns first, then refill their tuns and continue with the fly sparge technique.
In batch sparging you add volumes of water in equal amounts all at once, stir the grist, recirculate and drain until empty. You repeat until you have your boil volume (usually 2 or 3 times depending on the grain bill and equipment). It's faster than fly sparging, but many say unefficient compared to fly sparging. I batch sparge and hit my numbers every time now, where as with fly sparging I was getting inconsistient numbers. As far as which is actually more efficient, I don't know. I batch sparge, it's faster and if I lose a bit of efficiency, so be it. It's working for me.
To be fair though, fly sparging is supposed to be the more efficient method, which is debateable, I understand. Just pick a technique, develop it and see where it takes you.
well with a fly sparge, you want to mash your grains, then do not stir. if you stir what happens is you reconstitute the sugars back into the grist. during mashing the sugars have mostly dropped to the bottom of your tun with the water. your grain level should be slightly above your water level. then you have a sparge arm setup above your tun. you want to vourlof the first 2 quarts of runnings from your tun back onto your grains. this filters any grains that may have gotton through your false bottom. then with your drain closed, you want to start a slow fly sparge until you have about a 1-2 inch pool of water on top of your grist. then you want to open your drain so that the liquor drains at the exact same rate that your sparge water is entering. what this does is it presses the sugar down to the bottom of the tun with the fresh water acting as the press. once youre sparge water is out, just let the tun drain at the same rate. whatever you do, do not disturb the grain bed after you dough in the grains. keep in mind, you want your sparge to last between 20 and 40 mins. if its a short sparge, you are ineffective at pressing the sugars to the bottome. if its a long sparge, you lose too much temperature from your sparge water and you have incomplete conversion. so thats how you fly sparge. again, ive never done a batch sparge and i know brewers that have used that method and had inconsistent or bad results. but there are brewers that prefer the batch sparge and have mastered it. now what will really mess you up is a hybrid sparge where you utilize both methods. to my understanding, this takes a lot of time, but supposedly you can have efficiency numbers up above 90% easily with it.
anyway, lots of different teqniques, as with anything in life.
i have batch sparged from the beginning, and i have stirred between sparges, and i have taken first runnings, stirred with first sparge, and not with the second. my best efficiency has come from stirring between, and sparge drain is kinda slow.
i add the first sparge water (temp say, 189*) stir it up, leave for 3-4 mins, and start runnings. add secong sparge once i get no more wort for them tun into the pot, and lightly stir the top 2/3... no need to vorlauf the second sparge, as i did not upset my "filter".
anyway, thats what worked for me.
i have had about 3 weeks off due to alotta crap, but this weekend is a brew weekend unless i die or something like that.