How To Batch Sparge Inefficiently

[SteveD]

I posted this on the North Hants site in response to questions from Madbrewer, and then thought that there might be info here that some people may find useful in particular about batch sparging a bigger grain load than necessary, for lower extraction efficiency to give better quality wort - sorry, it's a bit of a big read.

Phil's message is in blue

Steve,

I am being a pain in the arse. But as I am definetely going to batch sparge my next brew. Could you list the important things i need to know in your opinion?

recipe [HTC] Hopeful TEA clone OG 1.044
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4500g pale
375g Crystal
20 litres desired in fermenter

what sort of efficiency is this compared to what I 'should' aim for (i.e. better beer for not being highly efficient?) Should I ramp up the grain bill even more to ensure no more harsh tannins? Maybe even 5kg & 400g respectively?

Method
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90 min mash at 66c in 18 litres of liqour
drain collect around 12 litres
heat 15 litres fresh liqor to 85c
(do I treat with crs - lower the PH to what what??)
mash grain in 85c liquor for another 20
drain off another 12 litres

boil the 24 litres(both batches) with the hops etc etc .......... should boil down to 20 litres in 90 mins.

just for info/ recipe completeness:-
8.5 IBU Fuggles (90)
7.5 IBU Fuggles (60)
16 IBU Goldings (60)
4 IBU Goldings (15)
2 packets danstar nottingham

thanks again for your help

Phil

Ok, first thing - the malt bill is fine in terms of getting 20L at OG1044 in the fermenter without having to wring the bejesus out of the malt. At 24L post boil, that's about 73% extraction efficiency which is fine.

I wouldn't be looking for 20L post boil, because you're not allowing for absorption by the hops during runoff, which might leave you 18L in the FV and 16-17L in the cornie post fermentation, whereas 24L in the post boil will give you 20L+ in the FV at 1044 and that will give you a cornie full easily after racking losses. Unless you want to mess about sparging your hops, I'd aim for 23-24L post boil which will give you plenty in the FV without having to wait ages for the last dregs to run off, or having to sparge hops. Always better to have too much wort, take what you want and throw some away, rather than not enough and having to dilute, etc.

Hops, IBU's looks ok, but what's with the 60 mins add? I'd just bung them all in for 90mins. Also, an addition at 15 mins is silly as that's obviously a flavour/aroma addition, but 15 mins boil will drive a lot of that off. Better to add the late hops at switch off and let them steep in the cooling wort. Tea is hoppy, so I'd a add between 1 and 2 ounces late.

Batch Sparging

Get a refractometer - it'll be the best £18 you'll spend.

You don't need to up the malt bill, though obviously you can if you wish, as I said, there's enough there as it is. Batch sparging doesn't run the risk of tannin/phenol/husk extraction in the same way as sparging does provided the mash bed doesn't get too hot, and your liquor isn't too alkaline.

Liquor - treat about 50L liquor in your big boiler with CRS to PH 7, or just below, but don't go mad, I mean PH 6.8-7. Throw in a crushed campden tab or two. You've got too much mash liquor in your method - 18L makes for a very thin mash. 15L would be just over 3L per kg, anything between 12.5L and 15L would be fine. Mash in, and check PH, if much higher than 5.2 wop in some Gypsum (Calcium sulphate) or DLS if you have it. Mash 90 mins-ish 66-67c.

While the mash is on, treat the rest of the liquor in the big boiler to PH6 or just below. You can use CRS for this, but it's much better to use Lactic or phosphoric acid - less brutal effect of PH, so not as easy to overdo. The reason for this adjustment is that if mash bed PH rises above 6 during sparge, it increases the chances of phenol (of which tannin is derived) extraction, and consequent off tastes and hazes. Though this is much less likely with batch sparging, it's still good practice.

Once done, fill your 26L boiler as full as it will go - you HAVE calibrated it, haven't you You kind of need to because unlike sparging where you just keep going until you've got it, batch sparging involves more precise measurement of liquor volumes, particularly if you want to stop short of maximum extraction. Place the HLT where you want it for sparging. . Dump the rest of the liquor in to a FV, or somewhere it can sit for a bit. Now your empty big boiler can be set to receive the wort.

Heat the sparge liquor up to about 90-95cc.

Calcs...

(1) preboil volume. I don't know about yours, but my twin element boiler boils off about 11L in 90 mins with both elements on, so if you want 24L post boil you need 35L preboil. You can adjust the calcs if yours is different. They say the best way to batch sparge is with 2 equal run offs from the mash so that's 17.5L per batch

First addition - say you mashed with 15L, and you have 4.875kg grain you can round that up to 5L lost to the grain (Grain absorbs about 1L per kg). Add more to the losses if your mash tun retains liquor in dead space. Mine is neglible if I tilt it to get the last bit.

So, 15L-5L is 10L wort available from the mash itself. To get the first runoff volume you therefore need 7.5L liquor added to the mash. Run it in fast and stir thoroughly - the mash temp will rise to somewhere between 70 and 75c, which is fine. Let it settle a minute or two, then reciculate with a jug until you see it's free of particles and starting to clear appreciably - then run all of it into the boiler. First run done.

2nd run - If you're going for high efficiency extraction, you'd now add the full 17.5L of liquor for the second run, but we're not doing that, we only want 73% efficiency to get 1044 at 24L.

First - If you add 14-17.5L at the first run temp of 90-95c, you'd overcook the mash bed for sure, so now add the cooling spare liquor to your HLT - this will drop the temp to about 85c. We won't need 17.5L, in my experience you should get what you need with 13-14L.

Now this next bit is why you need a refractometer.... and, you did calibrate your big boiler, didn't you?

Take a gravity reading of the first run, and note the volume collected. Keep one element on to start heating the wort towards boiling. More calcs now...Sugar points - a handy value, is simply OG xVol. We want 1044 at 24L, that's 44x24 = 1056 sugar points from our grain, from an available maximum of about 1450. (Wgt in kg x LDK lab extract figure) =72.8% efficiency required. So, from the first run you can calculate how many sugar points you've got already. You might be surprised to find that it's about 3/4 or more of what you need.

Now you know what you need.... ie 1056 less what you've already got. Say you got 800 in the first run, you want 256 from the second run. So, add the liquor, say 14L. Give it a good stir and measure the wort gravity in the mash tun(keep an eye on the temp, but is should be 70-77c) - it might be say, G1019. Now calculate the sugar points - 14x19 = 266. You've got it. Recirculate again to clear and run off the 14L and check the sugar points in the total runoff which should as near as dammit be what you want. If you didn't get enough sugar points with a 14L second add, whack in a bit more liquor!

Now you have 31.5L or so in the boiler, and all the sugar you need. Top up to 35L with more liquor from the HLT, and set it to boil, add hops, etc etc. As it approaches the end of the boil, check the gravity periodically, and switch off when you're about 0.2-0.4 brix below target gravity and you'll find it's virtually bang on 90 mins - if you know your evaporation rate, and you'll have about 24L post boil - plenty. Contraction and evaporation during cooling will nudge the gravity up to target. If you find you've overshot the gravity, then you can either settle for a slightly stronger brew, or dilute it in the boil to what you want, but making sure it does boil for sterility before switching off, and be content with more beer than you planned for.

There you go. There's a lot of detail there. I'm not saying that's how it HAS to be done, that's just how I do it, so use as much or as little of it that fits in with how you like to brew... There are many ways to skin a cat, and if you ask 10 brewers, you'll get 11 opinions.

Cheers,

Steve

[SteveD]

Very useful Steve although fortunately this is a very repeatable process so if anyone doesn't have a refractometer it isn't the end of the world. It only takes one brew to work out your efficiency at a set gravity, once you have that then you're all set for future brews without the need for measuring the gravity of the first batch. All that is required is to add sufficient sparge liquor in batch 2 to top up to final volume in the boiler as there will be no more losses, in other words what you put in you will get out.

Boil down to the post boil volume of final volume plus losses to the hops and trub in the boiler and you'll be able to run off the final volume into the FV with no further adjustments necessary. There's a batch sparge calculator to work out the volumes required here http://www.18000feet.com/calculators/ba ... lator.html

(thought that worth adding to avoid putting anyone off who was starting out)

Yes, that's all true. If I'm looking for a set level of highish extraction each time from the malt, that's what I'd do. Half the preboil volume from each batch, and, as you say, it's very repeatable - as long as the malt is consistent of course. As long as the temp and PH of the mash and sparge liquor are within limits, you're ok. It's very easy.

Although how to batch sparge inefficiently seems an odd goal to be trying to achieve, as you are maintaining a constant ph throughout the second batch sparge there is no advantage in reducing your efficiency to try and achieve a higher quality wort ?

If a lower efficiency was desirable to even further reduce the risk of extracting polyphenols and tannins then batch 2 requires more sugars to act as a buffer. An easy way to do this would be to estimate a new lower efficiency when designing the recipe, keep the rest of the process the same except add a litre less sparge water to batch one and a litre less to batch 2 then top up with 2L of fresh liquor in the boiler without the rest of the process changing. Not sure if I see the point though as you don't get the rising ph issue you do when fly sparging, particularly if you treat your sparge water to a ph of 6.

The lower efficiency sparge isn't about getting better quality wort through avoiding extraction of 'undesireables', as you're not going to get any with a well made mash and well conducted batch sparge anyway. It's about using a greater weight of malt than necessary and so getting enough of the good quality sugars from the malt to hit the desired OG and volume without resorting to the thinner end of the wedge. It's heading nearer towards no-sparge in that sense.

You still need to have good technique to make sure you get the good stuff, and so the low efficiency doesn't mean 'bad' it just means taking a lower proportion of the sugars, because there's more there to start with.

You can do it by trial and error, as you say - one brew to tone it in, but the refractometer takes most of the guess work out of it. Once you know what you have in batch one, you know exactly what you need from batch two, and can add and run off accordingly, without over diluting the mash. It's more precise. You could of course restrict the addition in batch one and add more in batch two. But by using a good deal more malt - 15-20% and sticking to the first part of the normal batch sparge formula, you get most of the rich sugars, about 75% or more of what you want, in the first run and only really have to top it up from the second run. The refractometer makes that process much easier and eliminates the need for trial runs, which you would need when changing OG's and volumes from brew to brew.

You could use a hydrometer as well, but it's a lot less convenient, plus waiting for the temperature to get within correction range means it takes a lot longer.

I thought I'd post the method because it would enable someone who normally fly sparged, or batch sparged to full efficiency, to be able to use a heavier weight of malt, restrict the extraction, and get it right first time, rather than finding at the end of the normal boil time that they might have to boil down more than planned, or throw wort away and dilute if their guess work goes wrong.

With fly sparging, it's also easy. Use as huge an ammount of malt as you like, run off and sparge. You know how many sugar points (Brewer's degrees x Litres post boil) you want, and when the collected wort hits that figure, you stop sparging. Then top up to preboil with plain liquor. Because you're taking off the richer sugars there's not a chance of getting anywhere near the danger zone of sub G1010, as long as your sparging technique is good.

If I want to, I'm able to whack in as much grain over the recipe ammount as I like, and at the end of the brew run the wort into the FV within a litre or so and 1 gravity point of what I intended, which is quite handy for club brews that are almost always to a specification.

I usually work on a weight of malt that gives me what I want at about 70 -75% extraction efficiency and 65% brewhouse efficiency. I used to chase after maximum yield and would get into the 90+% range regularly but one day I thought what on earth is the point? It does not make the beer any better at all, has many negative effects, and involves a lot of messing about. The only thing it does is save a quid or two on a bit less malt. Big deal!

[dcq1974]

Hey Guys
You mention a Refractometer below for £18. Where was this purchased? I take it this is a Brix refractometer and you have to convert to density (OG)?

Best Regards
Darren

[edit1now]

Something like this one on Ebay. High-quality Chinese product, very easy to use. You'll be lucky to pay only £18 though. The same ones are £50 from UK retailers.

[SteveD]

Ohh the forum looks different. The link to gainexpress on eBay is the right one for those refractometers. And yes, they are about £18.00 including the postage. The model shown is the lastest whizz bang one with illumination, I think, but I find the older one that hinges at the back of the sample plate is a bit easier in use. The older model is about £12.00 and a fiver postage. The seller is very good. Excellent service.