I clocked sparge speed w/ interesting results....

[jfowler1]

Last weekend, I brewed a Belgian Pale Ale. I designed the recipe around my typical 75% efficiency. I had made a couple adjustments to my equipment over the past 6 months (namely, opening my BC back up to factory setting and switching to a false bottom in my round MLT). I've always felt that my sparge went quickly, but never paid much attention to the actual time. I decided to clock my sparge from beginning to end.

After I collected 26 qts of wort (a pre-boil volume I keep constant), I stopped the timer....14 minutes!

I gave the kettle a few good stirs, and took 4 gravity samples with my refractometer. The result was as expected; 76% efficiency.

The typical convention I have seen is that fly sparging should be a long, slow process. After this test, I think the real hook for lautering is fluid dynamics. To break that down even more, I really support having a coarse crush and an optimized seperation medium that make it as easy as possible for the wort to navigate through the grain bed.

So long story short, if you are finding your efficiency to be inconsistent or offensively low, take a good look at fluid dynamics, and then ask yourself if it seems like you are making it easy for the wort to get through the lauter process.

Thoughts?

Joe

 

[mabrungard]

High efficiency demands a slow runoff. 14 minutes is pretty fast. I'm not surprised with the low efficiency. Doubling or tripling the runoff and sparging time should bring you into the 80 plus range. If your time is at a premium, then the quick runoff and low efficiency can be worth it.

 

[jfowler1]

If I can save 45 minutes for the cost of an extra pound of base malt, I would say that the quick lauter is well worth it.

More so....75% is low?

Every recipe in Brewing Classic Styles is based on 70%. I believe that BYO prints recipes at 65%.

I had been brewing at around 88% for a couple of years, but I really wanted it lower. I felt that in exchange for the higher efficiency, I was costing myself time and tannin extraction. Since getting down to 75%, I find the wort much richer. I am certainly an anti-sparge kind of guy; if I had a larger Mash Tun, I would probably go with no-sparge.

Martin, you are much more of a water guy than I am. Is there any basis for concern with a slower sparge, namely, tannin extraction?

EDIT-

And another thought. Gordon Strong talks a lot about the negatives of highly roasted grains over staying their welcome in the mash. The lauter is basically an extention of the mash. I do not go as far as top mashing, but wouldn't the quicker lauter would really play into Gordon's thoughs about extraction from roasted grains.

 

[OLDBREW]

if your runoff tastes sweet and your ph is under 6, there is no concern with tannin extraction. I also think that a 14 minute fly sparge is to fast.

I'd say 26 to 30 minutes will give you a much higher mash efficiency, and still have a very good malt profiled wort.

black patient may give you astringent results in a mash, but that really is what the malts made to do. adjust the amount used for the flavor profile. 90 minute mashes are not required on most dark malt or unmalted recipes to begin with

 

[jfowler1]

I must have been unclear in the first post.

I am thrilled with my 75% efficiency. It is consistent, and is basically a natural outcome of my brewing process. I have said this before, but I believe that your system should dictate your efficiency, instead of letting efficiency dictate your system. It is not like a grade; "higher" does not equal "better".

I opened up the thread because I wanted to talk about the correlation of fluid dynamics and efficiency, as opposed to run-off speed and efficiency. Clearly, most people know the latter correlation, but it seems that not enough people pay attention to fluid dynamics. The speed of the lauter is meaningless if the wort can't flow sideways through a bed of powder on its way to a braided lav supply.

14 minutes does seem insanely fast, and that is why I wanted to talk about this - the reactions actually play exactly to my point. I think that my test showed that if your lauter equipment is optimized for fluid dynamics, you can expect good, consistent efficiency, regardless of lauter speed.

 

[JoePro]

This is a great post-- I have only recently found out that my sparges are exceedingly too slow (90 minutes). This has given me efficiency problems because the grain bed compacts.

jfowler, what do you do to get your grain bed up to the mid-high 160s?

 

[OLDBREW]

I must have been unclear in the first post.

I am thrilled with my 75% efficiency. It is consistent, and is basically a natural outcome of my brewing process. I have said this before, but I believe that your system should dictate your efficiency, instead of letting efficiency dictate your system. It is not like a grade; "higher" does not equal "better".

I opened up the thread because I wanted to talk about the correlation of fluid dynamics and efficiency, as opposed to run-off speed and efficiency. Clearly, most people know the latter correlation, but it seems that not enough people pay attention to fluid dynamics. The speed of the lauter is meaningless if the wort can't flow sideways through a bed of powder on its way to a braided lav supply.

14 minutes does seem insanely fast, and that is why I wanted to talk about this - the reactions actually play exactly to my point. I think that my test showed that if your lauter equipment is optimized for fluid dynamics, you can expect good, consistent efficiency, regardless of lauter speed.

a cylinder shape vessel (keggle) with a full perforated false botton, the pick up tube place directly in the middle, is the best hands down for fluid dynamics. the crush (as you pointed out) has to be tweaked to your system to prevent compaction or channeling.

even with the perfect setup there is what is called wasting sugars from sparging too fast and also chance or developing channels.

I find 1 qt per minute is a very good flow rate that boosts your efficiency and keeps your wort profile as good if not better taste wise.

just my 02 cent from many many years of brewing and experimenting with different types of gear

 

[jfowler1]

a cylinder shape vessel (keggle) with a full perforated false botton, the pick up tube place directly in the middle, is the best hands down for fluid dynamics.

I like the cooler because of its ability to hold mash temps steady, but the rest of your description jives (see pic below). I think your comments about wasting sugars is dead on - I am sure that plenty is left behind. I simply don't care. You would also be horrified by the amount of wort that is left behind in my MLT when I decide to cut off collection. I probably drain about 2 gallons of final runnings into the street, but IMO, the highest quality wort has already been collected. To sparge an extra gallon or so, just to rinse every last bit of sugar, seems like a bigger waste than 75% vs 85%. It will require more fuel for a longer boil, and again, that increases the duration of brew day. I'll take time savings with consistent results all day over saving $1.12 in base grain or producing an extra half gallon of beer. For me, time is by far the more valuable commodity.

"what do you do to get your grain bed up to the mid-high 160s?"

I try to leave about a 1/2 to a full gallon of head space in my MLT. I measure and raise sparge water in my kettle to about 175F, and transfer via pump to my HLT (a second 5 gallon cooler). I leave about 3 qts of sparge water in the kettle post-transfer, and bring it to a boil. That "mash-out" water gets infused into the MLT, I give it a good stir, and automate a 10 minute recirculation. That gets my mash just above 160F - the temp doesn't mean that much to me, I just want the mash as thin as possible so there is plenty of liquid for recirc. I feel the recirculation gets some sugars into solution, and more importantly, helps set a grainbed for filtering. After 10 minutes or recirc, I rearrange some hoses and sparge with water that is now just below 170F. About 15 minutes later, my kettle is full of wort.

If you want to see the whole thing illustrated, google 1550 "lite". It will be the first link.

Joe

 

[OLDBREW]

I'm running a gas fired herms system indoors now, so the mashtun doesn't need to be insulated. still the same principle as yours.

i"ll bring my grainbed temp up to 168*F at mashout. I stir the grainbed to even out and break up any silt that had formed during my mashing regime, then hold that for 10 minutes to reset the bed, then recirculate till clear, then start the sparge

 

[BlackJaqueJanaviac]

I'm quite new to brewing, however I have some knowlege of fluid dynamics.

How long is your braided tube?

The more surface area of the braided tube the slower the wort will flow through that surface yet can still contribute to a large flow at the end of the tube.

For example: If your tube is say 3/4-inch diameter and 10 inches long you have 24 sq. in. of surface area for wort to flow into the tube. If you're collecting wort at a flow of 2 qts/min the flow through that 10-inch braid is 0.08 qts per square inch per minute. If you use a 20-inch braid and maintain the discharge at 2 qt/min the flow through the braid will be 0.04 qts per sq. in. per minute, much slower.

When I made my mashtun I intentionaly bought the longest braid I could find - I think it was 30 or 36 inches. I've always had fast lautering and sparges and my efficiency is right up there (unless I'm calculating something wrong see my other posts). Never a stuck mash.

Now the guys who use false bottoms on round mashtuns might have a different deal. Sure their surface area of the bottom is greater than a two-foot braid, but the number of holes is likely much less.

Another thing that affects the transmissivity of the mash is the consistancy of the particle size of the grain. Believe it or not, a bathtub full of marbles has as much air space between balls as a bathtub full of bowling balls. But if you fill the bathtub full of bowling balls AND marbles you'll have a fewer channels for fluid to pass through. Apply this to your crush. Size should not matter as much as consistancy (down to a point).

If your grain crush produces evenly sized particles your odds of stuck mash should be reduced. Imagine the pore spaces between particles is roughly 0.1 mm. As long as all your particles are >0.1 mm the particles will stay put. But if there are some particles that are 0.05mm they will dislodge and plug the pore spaces between larger particles.

In the real world we will never have a perfectly even crush. So one way to keep those flow-paths open is to keep the flow slow so as not to dislodge any small particles.

I'm sure there is a point where even a perfectly consistant crush size will impede the flow of wort. Probably somewhere less than 0.074mm. Somewhere below this point the pore spaces between particles gets so small that friction and molecular adhesion of the water will inhibit flow.

 

[BlackJaqueJanaviac]

You know. Now that I see that picture of the mash tun I wonder if a guy couldn't make a filter using those pleated paper swimming pool filters.

Run the drain tube to the middle of the tun, put a 90* elbow facing up. Set the filter on the elbow and seal the top hole of the filter with a plug of some sort.

There's a LOT of surface area on those pleated filters so flow through the filter would be slow, yet discharge flow would be great. Not to mention vorlaufing might be unnecessary.

 

[OLDBREW]

when you use a perforated full false bottom.. if you are crushing your grain too fine, it produces flour. the flour when recirculated using a pump, will make a layer of silt on the top of the grain bed, which in turn will compact the grainbed. this can allow channeling to occur or a stuck sparge. A single braid in a cooler is the least efficient in fluid dynamics when using the fly sparge method.

When using a braid and batch sparging, you can bring the crush much smaller because the braid wont clog. you stir the complete grainbed to make sure your sparge water is evenly distributed between the bits of milled grist to get to the trapped sugars. fluid dynamics doesn't need be apllied when batch sparging, and the speed of emptying the mash/lauter tun doesn't change the efficiency rate either.

 

[OLDBREW]

You know. Now that I see that picture of the mash tun I wonder if a guy couldn't make a filter using those pleated paper swimming pool filters.

Run the drain tube to the middle of the tun, put a 90* elbow facing up. Set the filter on the elbow and seal the top hole of the filter with a plug of some sort.

There's a LOT of surface area on those pleated filters so flow through the filter would be slow, yet discharge flow would be great. Not to mention vorlaufing might be unnecessary.

back some years ago, guys were using the scubber pads from professional disc cleaner/polishers in the gott coolers with very good success.. then someone found out they may of been harmful to your health

 

[mabrungard]

Martin, you are much more of a water guy than I am. Is there any basis for concern with a slower sparge, namely, tannin extraction?

EDIT-

And another thought. Gordon Strong talks a lot about the negatives of highly roasted grains over staying their welcome in the mash. The lauter is basically an extention of the mash. I do not go as far as top mashing, but wouldn't the quicker lauter would really play into Gordon's thoughs about extraction from roasted grains.

I routinely get around 80% with about a 20 to 30 minute runoff. 75% is still plenty good.

If your sparge water has very low alkalinity or has been acidified to adequately reduce its alkalinity, runoff duration should have little effect on tannin extraction. I suppose that a slow runoff with high alkalinity water could produce more tannin extraction.

Gordon brews with RO water which has very little alkalinity. That makes any acidic grain in his grain bill a negative. He rightly avoids that in his brewing.

For someone with brewing water with high alkalinity, they definitely would want to mash with their roasted malt and crystal malts to help cut the alkalinity of their water and bring the mash pH into a proper range. That is a perfect example of why places like Dublin, Edinburgh, and Munich developed great proficiency with dark beers.

On top of what Gordon mentions, another of his goals is forming the beer flavor with all the tools at his disposal. In the case where he was primarily interested in the color contribution of the roasted malt and not the roastiness, then avoiding the hot mash is a good idea. If you wanted those flavors, then including them in the hot mash might make sense.

Enjoy!