How do you handle the vorlauf phase in a recipe while using the BIAB method?
If you have an overhead hoist point (highly recommended), at the end of the mash lift the bag and tie it off. Immediately fire the heat for the boil. Let the bag drip into the kettle for the duration of the boil, by which time it will be fully drained (only a cup or so of liquid will remain in the grains). If you have finely milled your grains (~.025") you can easily achieve efficiency in the low 80's with this method.
Heres an interesting article on sparge vs no sparge: Sparge VS No Sparge - Grainfather Community
There's a Brulosophy experiment where they did a much better job of keeping the gravities similar. 14 of 26 testers were able to distinguish the difference between the beers. That result achieved statistical significance, but not by an overwhelming margin (13 were required to achieve significance).
I only sparge if I'm shooting for a gravity above 1.065, because efficiency does take a small hit with the larger grain bills required for big beers.
@doug293cz has some cool graphs showing the phenomenon posted around here somewhere....
Since you mentioned it, here is the chart again. This shows lauter efficiency for different numbers of batch sparges (starting with 0) for two different grain absorption rates. Mash efficiency = conversion efficiency * lauter efficiency, so if your conversion efficiency is less than 100%, then your mash efficiency will be lower than what the chart shows....
@doug293cz has some cool graphs showing the phenomenon posted around here somewhere. And I built a mash efficiency predictor in my sheet that estimates changes in mash efficiency resulting from changes in grain bill sizes and/or sparge methods (and also taking into account the user's brewhouse parameters). I did that because it's not really very intuitive to (I think) most people, and sure beats guessing.
I think you are correct. Search “all grain absorbtion rate”. Its largely agreed on at about .12 gallons per pound. .12 in fractions is an eighth. And a pint just happens to be an eighth of a gallon. So we lose about a pint of water/wort per pound of grain to absorbtion. To me, this is a good case for sparging.@LittleRiver ok, if you're doing 5 gallon batches, there's a lot more than a cup of wort left behind in your grains. I'm not just talking about liquid you can see pooled somewhere, but also what's been absorbed. If you could actually make that happen (just one cup of loss), you'd be getting mash efficiencies in the very high 90s.
Yes, the mash concept is the same, plus most have an integrated pump for recirculating and racking - very nice convenience, and electronic temperature control, which is effective at maintaining the mash temperature.And all of these electric brew systems like Grainfather, Robobrew, etc are functionally identical to biab. They just use a basket to hold the grain instead of a bag. Most of them provide instructions to brew with a sparge step or no sparge step.
Yes, the mash concept is the same, plus most have an integrated pump for recirculating and racking - very nice convenience, and electronic temperature control, which is effective at maintaining the mash temperature.
Yes true and I wasn't trying to imply it was helpful in a sparge. I always sparge with my Robobrew, usually in the neighborhood of 2.5-3 gallons, mash pipe raised and pump off. I also believe that recirculation during mash has the potential to extract more sugars.The big difference is they recirculate during the mash while the grain is fully immersed. There is no recirculation back through the grain once the basket is lifted. So this is not the equivelant of a sparge or vorlauf step. Recirculation through the immersed grain on an electric system is mostly done to maintain a constant temp throughout and avoid hot spots around the heating elements.
At best recirculation can speed up conversion a bit. This may allow better conversion efficiency in cases where conversion is incomplete at the end of the allotted mash time, so you get more conversion in the same amount of time. You can get the same level of conversion by extending the mash. Using a finer crush has an even larger effect on speeding up the conversion rate. You can get 100% conversion with any of these methods with the appropriate length mash, provided the enzymes aren't all denatured before the end of the mash.Yes true and I wasn't trying to imply it was helpful in a sparge. I always sparge with my Robobrew, usually in the neighborhood of 2.5-3 gallons, mash pipe raised and pump off. I also believe that recirculation during mash has the potential to extract more sugars.
0.12 gal/lb is the typical absorption rate for a drained MLT. Since a suspended bag applies some compression to the grain mass, it will typically have a lower absorption rate - 0.10 - 0.08 gal/lb, or even lower, depending on draining time. Squeezing the bag can drop absorption to 0.08 - 0.04 gal/lb. Reducing grain absorption increases the lauter efficiency, and can partially make up for the efficiency lost due to not sparging (see the chart posted previously in this thread.) BIAB systems, particularly if they don't recirculate, can employ a much finer grain crush than other systems, and can often get higher conversion efficiency. The lower grain absorption, combined with higher conversion efficiency, often allows BIAB systems to obtain mash efficiencies equal to sparged traditional systems. There are many anecdotal accounts from BIABers on HBT who found they didn't need to make any adjustments to grain bills (to compensate for lower efficiency) when moving to BIAB.I think you are correct. Search “all grain absorbtion rate”. Its largely agreed on at about .12 gallons per pound. .12 in fractions is an eighth. And a pint just happens to be an eighth of a gallon. So we lose about a pint of water/wort per pound of grain to absorbtion. To me, this is a good case for sparging.
Heres an interesting article on sparge vs no sparge: Sparge VS No Sparge - Grainfather Community
“CONCLUSION:
The no sparge beer takes [sic] a big hit on efficiency when compared to the sparged beer and when given to a panel of tasters the majority were able to identify the difference and preferred the sparged beer.
JK was happy with both beers and would drink either though it was very obvious that the sparged beer was better, with a more rounded flavour and better aroma. JK suggests if you’re looking to save time on the brew day you can get away with skipping the sparge step but if you’re looking to make a beer that is better than ‘passable’ then sparging is a very necessary step.“
I‘ve always sparged, first on a 26 gallon three vessel system and now on a 35L Robobrew. On both systems I’d be challenged to fit enough water into the mash and achieve the desired volume out. Also, I don’t typically take steps to speed up my brew day or my fermenting.
The big difference is they recirculate during the mash while the grain is fully immersed. There is no recirculation back through the grain once the basket is lifted. So this is not the equivelant of a sparge or vorlauf step. Recirculation through the immersed grain on an electric system is mostly done to maintain a constant temp throughout and avoid hot spots around the heating elements.
At best recirculation can speed up conversion a bit. This may allow better conversion efficiency in cases where conversion is incomplete at the end of the allotted mash time, so you get more conversion in the same amount of time. You can get the same level of conversion by extending the mash. Using a finer crush has an even larger effect on speeding up the conversion rate. You can get 100% conversion with any of these methods with the appropriate length mash, provided the enzymes aren't all denatured before the end of the mash.
Basket and malt pipe systems have an issue that affects lauter efficiency, because the wort outside the basket/pipe is of lower SG than the wort within the basket/pipe. If this isn't mitigated before, or as a part of, lautering, the lower density wort drains freely, and the wort retained due to grain absorption is the higher density wort. Thus more sugar is retained in the grain mass after lautering, and lauter efficiency is lower. Recirculation will homogenize the wort under the basket/pipe with the wort inside, but will have limited effect on wort in the lateral space between the basket/pipe and vessel wall. The effect will be worse for a pipe than a basket, and depending on flow patterns, there may be no effect for a basket. The better the wort is homogenized before lautering, the higher the lauter efficiency will be.
Brew on
The wort between the pipe wall and kettle wall doesn't really participate in the recirculation. Read this thread.Doug, not sure I agree with your second paragraph. With a malt pipe (solid sides), if you recirculate and return back into the pipe, drawing off the bottom will pull from both the sides and the pipe. I would not expect the liquid on the sides of the pipe (between the pipe and the kettle wall) to just sit dormant. Wort will flow more easily through that passage than it will down through the grain, so I'd expect wort drawn off the bottom to at least partially consist of wort from that space. Over an hour long mash with recirculation, I'd expect the wort to be pretty consistent with respect to gravity throughout the system. What am I missing?
The wort between the pipe wall and kettle wall doesn't really participate in the recirculation. Read this thread.
Brew on
You mean something like this?Or split the recirc between inside the basket and outside. That will allow more recirc volume total.
A little bag squeeze never hurt anyone.... I squeeze mine all the time.Vorlauf, mash out, sparging, and bag squeezing are all things that can be safely eliminated from a BIAB process.
If you have an overhead hoist point (highly recommended), at the end of the mash lift the bag and tie it off. Immediately fire the heat for the boil. Let the bag drip into the kettle for the duration of the boil, by which time it will be fully drained (only a cup or so of liquid will remain in the grains). If you have finely milled your grains (~.025") you can easily achieve efficiency in the low 80's with this method.
Coarsely milled grains or a high gravity target (above ~1.065) can cause your efficiency to take a hit, in those cases you may want to add a sparge step.
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