Double batch sparge, +6% eff.

[Fore]

I'll add to the double batch sparge discussion.

For those who are not sure what it is...
A normal batch sparge has 2 drain offs. The first drain is the topped up mash water. The second drain is fresh water added (the rinse). In a double batch sparge, you add fresh water twice, and so drain off 3 times (2 rinses).

I recently switched from single batch to double batch, and can say that I have roughly increased my efficiency by about 6%.

To save time, I have decided not to split the output into 3 even drains. In practical terms, this means that I drain straight from the mash. I skip the initial mash top up, mix in, leave 10 minutes etc. I divide the top up water between the 2 subsequent rinses. This way, I haven't added much extra time to a single batch sparge, because I always mixed and waited twice for the bed to settle in any case.

The few minutes added seem well worthwile for a 6% gain.

 

[JapanBrew]

Sounds interesting. I'll have to give it a shot.

 

[Cwrw666]

This would be fairly easy to do for BIABers. I squeeze out my bag then do a single dunk sparge in an FV with a few litres of hot water, and squeeze out again. Easy enough to have 2 vessels ready with sparge water in each to do a double one. Might well give this a go myself.

 

[mike-os]

I have always done 2, thought that was what everyone did?

recently started doing 3 measuring the sg of the runoff until it hits 1.015 or thereabouts .... third run is about 6l or so depending on what the last run was like.

I am going to be recalculating grain bills as I am typically getting 28l post boil now

 

[MyQul]

Be careful with this. I do a double dunk sparge as I make a concentrated wort so it needs it. But just recently I've began to notice a slight touch of astringency. I've always done two dunk sparges so me noticing the the astringency now makes me think my palette might be getting a bit more sensitive to it.
I'll continue to do the two dunk sparges in future but with less water.

 

[LarryF]

This would be fairly easy to do for BIABers. I squeeze out my bag then do a single dunk sparge in an FV with a few litres of hot water, and squeeze out again. Easy enough to have 2 vessels ready with sparge water in each to do a double one. Might well give this a go myself.

Cwr can I ask, what temp is your water when you dunk sparge? I've tried two AG's and I've had the same off flavour in both. My sparge water was 80c and I'm tempted to drop it to 70c to try an eliminate this.

 

[MyQul]

Cwr can I ask, what temp is your water when you dunk sparge? I've tried two AG's and I've had the same off flavour in both. My sparge water was 80c and I'm tempted to drop it to 70c to try an eliminate this.

80C is way to hot for sparging. Your going to draw tannins at those temps afaik 76C is the max temp you want to sparge at. I sparge at 75C

 

[mike-os]

It is important to ensure the sg does not go below 1.012 and the temp over 77c

 

[LarryF]

80C is way to hot for sparging. Your going to draw tannins at those temps afaik 76C is the max temp you want to sparge at. I sparge at 75C

Nice one MQ, much appreciated.

 

[Fore]

I think pH plays a part here also. I think the risk of extracting tannins needs both >6 pH plus more than 77 degree bed. I treat all my water with acid, plus I add batch water at about 82 degrees and mix quickly, which results in a bed of 75 degrees. So far so good; I'll make adjustments if tannins start to come though, but I think the chance of that is small.

 

[Fore]

I have always done 2, thought that was what everyone did?

recently started doing 3 measuring the sg of the runoff until it hits 1.015 or thereabouts .... third run is about 6l or so depending on what the last run was like.

I am going to be recalculating grain bills as I am typically getting 28l post boil now

I think you misunderstand double batch sparge. A normal batch sparge has 2 run-offs, a double batch sparge has 3 (of which 2 are technically the sparge rinse). I doubt you do a triple batch sparge, so I guess you've recently taken the same step as me.

 

[MyQul]

I think pH plays a part here also. I think the risk of extracting tannins needs both >6 pH plus more than 77 degree bed. I treat all my water with acid, plus I add batch water at about 82 degrees and mix quickly, which results in a bed of 75 degrees. So far so good; I'll make adjustments if tannins start to come though, but I think the chance of that is small.

PH plays a big part. When I was reading up on tannins (do to some hop astringency problems I had a couple of month ago). Iirc the reason why tannins are extracted when you over sparge is because the acids in the grain acts as a PH buffer. If you oversparge (too much water) your diluting the grain acids

 

[mike-os]

I think you misunderstand double batch sparge. A normal batch sparge has 2 run-offs, a double batch sparge has 3 (of which 2 are technically the sparge rinse). I doubt you do a triple batch sparge, so I guess you've recently taken the same step as me.

I do post mash runoff
Sparge and runoff
Sparge and runoff

as standard....

last 2-3 brews I have added another sparge and runoff as I was seeing 1.022 or so in the last sparge

 

[Fore]

I do post mash runoff
Sparge and runoff
Sparge and runoff

as standard....

last 2-3 brews I have added another sparge and runoff as I was seeing 1.022 or so in the last sparge

OK I take it back. I've never heard of anyone doing a tripple batch sparge before. The debates I read are always around single or double.

In my case I have quite a large boil off rate (26% @ 75min.), which means I use quite a lot of water, which lends itself well to a double batch sparge. It means that my mash water is about the same or slightly less than the 2 subsequent sparges. If I were to add a 3rd sparge, then given that the mash liquor to grain ratio needs to stay within a certain range, I'd end up with a lot less water in my sparges, even with the large volume of water I do use. So how do you overcome that? Do you also have a big boil off rate or long boil, or just use less water in your sparges?

I read you mentioned increasing the grain bill to compensate for the 28l post boil. But if you did that you'd have to up your mash water and get into chasing your tail. If I understand right what you are saying, you'd either need to boil longer (or more vigorously), or reduce the sparge volumes. Bt the latter might return a lower sugar extract, so again you'd be chasing your tail. As far as I can tell from my experience, if you use more water to extract the sugars, then the only real solution is to boil it away.

 

[mike-os]

Boiling longer ups the og beyond the target. .... Following a 'standard recipe' I am currently getting 28l at target gravity. Therefore I should be able to decrease grain bill to compensate for the higher efficiency of the mash process....The extra 5l is a 20% increase so even a 10% reduction in grain can be significantly cheaper. .. on the half hearted brew it's nearly 1kg

Following some reading on fly sparging where advice is to stop before 1.012, I thought hang on, am I wasting sugar here?

Usually 2 batch sparge will take the majority of the sugar, give sufficient volume and is efficient enough for most people, I like to find the practical limits.

I tend to do a slightly longer mash to, at about 75 to 90 minutes

 

[BeerCat]

I have noticed when i do a dunk sparge the wort does not taste very nice even though with adjustments for temp it still says 1020. Is this just because the 1st run tastes so good? Should i not worry about this?

 

[mike-os]

Later running do taste bland... first runnings can be over 1.10 so very concentrated

 

[Fore]

I return to this my earlier thread to say don't do this, or at least take great care. Although I did significantly improve my efficiency with the implementation of double batch sparge, I ended up extracting tannins.

I learnt my lesson and will revert back to single batch sparge and pay the few pence for the few extra grains needed.