Sparging

[Clive125]

Hi everyone,

Just a quick question as I am new to all grain brewing, when sparging the mash at what point is the SG taken, is it done by taking a sample of the run off from the mash tun every so often or do you monitor the reading of what is actually going into the boiler as a whole and stopping when the SG drops to a certain level.

Clive

[MTW]

If you're trying to avoid over-sparging then it's the run off from the mash tun that's usually monitored, making sure it doesn't drop too low (often agreed roughly 1.010, ball park) as the sparge goes on. If you're after a pre-boil SG, then it's when everything is mixed in the boiler.

[Fil]

Hi Clive welcome to Jims.

Have you considered batch sparging, its a lot simpler, and if you have a calibrated bucket to drain the batches into its very easy to hit volume targets.

Once you mash is complete simply fill (top up) the tun with your sparge liquor, and give it a good stir and let it settle for 25-30 mins, then drain the tun into a bucket that will measure the volume drained. Once drained subtract the volume of liquor you have collected from your preboil target (28l? if your goal is 23l and you expect a 5l boil off), and the result of PreBoil-Target - 1st batch collected is the volume you need for batch sparge #2

No risk of under/over sparging at all, Some will argue batch sparging is less efficient, tbh i cant say ive noticed it, but i will add an extra handful or 2 of grain to compensate just n case when i remember..

[Kev888]

..when sparging the mash at what point is the SG taken, is it done by taking a sample of the run off from the mash tun every so often or do you monitor the reading of what is actually going into the boiler as a whole and stopping when the SG drops to a certain level.

A key aim with fly/continuous sparging is to avoid going too far and rinsing out significant undesirable stuff from the grain. So goings on in the mash/lauter tun are the things of importance here, not so much the kettle. The run-off is a convenient place to get indicative samples, so people typically take regular samples of the run-off at least towards the end of the sparge. EDIT: you should cool the wort to the hydrometer's (or refractometer's) calibrated temperature before measuring, which may take a little time - one of several reasons for sparging slowly and steadily.

That said, the gravity of the run-off is only an indirect guide to what is happening, and you may choose higher or lower limits than the common 1.010. The quality of wort being run off reduces faster towards the end of the sparge, and it may do so sooner for one brewer than for another (say an expert doing a slow, very even sparge with liquor prepared to manage the sparge pH). Some people also taste the run-off, as another measure, in case anything astringent starts coming through. My advice would be to not push it too far initially; you can always use a tad more grain if needed to achieve the gravity wanted with less sparging.

EDIT2: The above is for fly or continuous sparging. Generally speaking 'batch sparging' isn't in too much danger of the gravity or pH getting out of range (unless you do more batches than is normal) and the run-off from each batch will all be about the same gravity too, so this technique doesn't require such continual monitoring of the run-off.

The other key aim is to get what you want in the kettle/boiler. You may well choose to stop sparging sooner than necessary, once you have achieved enough volume and gravity of wort. Especially on higher gravity brews, sparging longer than needed extracts more stuff from the grain but also dilutes the wort in the kettle, requiring you to then boil for ages to reduce it down. For many/most home-brew situations this may not be worth the time and energy.

[Kev888]

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[Carnot]

Clive,
I am not sure what sparging equipment that you are using but I made a sparger from a shower head from Toolstaion. It works brilliantly. It is 300 mm across and rains onto the grain bed and distributes well. I hold it in place with a lab stand. I connected it to my tea urn with a length of silicone tubing.
I got the idea from Dave Line's Big Book of Brewing.

Toolstation item number 77110. There is a smaller version 46994.

[sbond10]

Could the same be used with a s/s watering can rose and a funnel ?

[orlando]

Hi everyone,

Just a quick question as I am new to all grain brewing, when sparging the mash at what point is the SG taken, is it done by taking a sample of the run off from the mash tun every so often or do you monitor the reading of what is actually going into the boiler as a whole and stopping when the SG drops to a certain level.

Quick answer, the former, the latter would not alert you to the last runnings giving you a potential problem, I'm assuming the S stands for specific. Kev gives you most of the answer why. A little more explanation as to why it is important is because as you sparge you dilute the wort and therefore its ability to keep the mash pH low. If you are sparging with liquour high in alkalinity you limit the grains ability to keep the pH in the 5.2-5.6 range. It is this that can begin to leech undesirable elements from the mash. The rule of thumb is to stop sparging below 1.010 but to be honest if the pH of the wort going into the kettle is below 6 it shouldn't be that much of a problem. As an addendum make sure your sparge water is low in alkalinity regardless of the style; another reason why treating water for dark beers isn't simply a question of treating all the liquour for the brew the same.

[Clive125]

Thank you for all the replies, I think to start with and be on the safe side I will check the SG of the spargings at regular intervals in line with the information Orlando gives. I find that none of the books I have give a real hard clear answer on this, only to stop when the specific gravity drops to 1.010. So I was a bit confused as to whether this reading was taken from the wort in the boiler as sparged from the mash tun or the spargings themselves as they come out of the mash tun itself at regular intervals.

Clive

[MTW]

Be aware that your throughput speed will have an effect. I've had runnings drop below the point I'm looking for, only to realise I need to slow the sparge down a bit, and see them get back up again.

In my coolbox, I get good results fly sparging at 0.5L per minute, which is a pretty small stream. My advice would be to hold a tube into a measuring jug from the HLT and get used to what (say) 0.5L/min and 1L/min roughly look like. Then you can treat your runnings SG with a bit more importance, once you've got a grip of the flow rate in and out.

Set your efficiency expectations deliberately low for a while, and you may find you get the volume expected without the SG touching the minimum you want out of the tun. Better to work back from there than the other way around IMO.

[jonnymorris]

As above but;

I don't bother checking the SG until near the end of the sparge (and rarely even then) but the point is regular readings may be overkill and,

You'll need to do a temp correction for the SG reading... I recall stopping at a reading less than 1.000 (and certainly not 1.010) to account for this.

Sent from my E6653 using Tapatalk

[Kev888]

You'll need to do a temp correction for the SG reading... I recall stopping at a reading less than 1.000 (and certainly not 1.010) to account for this.

Ha, I was just adding an edit to my post as you mentioned this.

It is usually better to cool the wort to the correct temperature than do a mathematical correction to compensate, but for these purposes it probably doesn't matter much provided you do one or the other (and are consistent). Speed is important with a changing picture, and cooling to the proper temperature can take quite a while with hydrometer-sized samples.

I would suggest cooling the wort to 'vaguely' normal temperatures though, partly to help accuracy and partly because some instruments may be damaged by mash temperatures or temperature shocks. That is how my first ever hydrometer met its end..

[MTW]

You'll need to do a temp correction for the SG reading... I recall stopping at a reading less than 1.000 (and certainly not 1.010) to account for this.

Ha, I was just adding an edit to my post as you mentioned this.

It is usually better to cool the wort to the correct temperature than do a mathematical correction to compensate, but for these purposes it probably doesn't matter much provided you do one or the other (and are consistent). Speed is important with a changing picture, and cooling to the proper temperature can take quite a while with hydrometer-sized samples.

I would suggest cooling the wort to 'vaguely' normal temperatures though, partly to help accuracy and partly because some instruments may be damaged by mash temperatures or temperature shocks. That is how my first ever hydrometer met its end..

It's the main time I use a refractometer, which may not be perfect, but gives a guide brew to brew, which is the main thing for me.

[orlando]

You'll need to do a temp correction for the SG reading... I recall stopping at a reading less than 1.000 (and certainly not 1.010) to account for this.

Ha, I was just adding an edit to my post as you mentioned this.

It is usually better to cool the wort to the correct temperature than do a mathematical correction to compensate, but for these purposes it probably doesn't matter much provided you do one or the other (and are consistent). Speed is important with a changing picture, and cooling to the proper temperature can take quite a while with hydrometer-sized samples.

I would suggest cooling the wort to 'vaguely' normal temperatures though, partly to help accuracy and partly because some instruments may be damaged by mash temperatures or temperature shocks. That is how my first ever hydrometer met its end..

Dare I mention the R word? Not a big fan of refractometers but this is one time when they can be useful. I now don't bother taking measurements as I'm reasonably confident my water treatment measures deal with the issue. Proofs in the beer.

[Kev888]

Yes i use a refractometer to measure the run-off too, though like many I used the hydrometer for years beforehand. The main difference in this role IMO is sample size; the wort sample should ideally still be cooled but the tiny amount involved is 'much' quicker to do that with. So the refractometer is more convenient, though it doesn't mean the hydrometer is invalid if that is what one has.