Sparge Times

[Samwise Gamgee]

I just completed my 3rd AG on the weekend and each time I've had quite a long sparge.

I know a slow sparge is desirable to prevent compacting the grain bed but how slow is too slow.

It took 2hrs to get approx 35L of wort from just under 5kg of grain in a cylindrical keep cool esky with s/s false bottom. That was with the tap completely open too.

Is this normal? I seem to remember seeing other ppl taking about an hour or so to retrieve the same volume.

I get air bubbles up the racking tube, would this be slowing it down? As the flow looks quite fast out of the tap into the tubing but then seems to slow down somewhere along the tube.


any advice would be appreciated.

cheers

EDIT: Method is fly sparging

 

[pint of lager]

Welcome to the world of ag.

Two hours is way too long. There is something not right with your setup. By opening and shutting the tap, you should go from full flow to no flow, so that you control the flow rate, be it sparge in 10 minutes or sparge in 120 minutes.

A slower sparge flow is beneficial for high efficiencies. A faster flow rate means the brew day goes quicker. You as the brewer get to decide, do you add a bit more grain and sparge quicker, or sparge slower with a longer brewday but better efficiency.

The usual culprit for stuck or slow sparges is too fine a crush. Too fine a mesh in your false bottom may also be the culprit. A large percentage of wheat in the grist will cause a slow runoff.

Running off too quickly initialy may compact the grain bed. To help fix this, blow air back up the runoff tube.

You want your false bottom to have large enough holes to block most of the grain. As you runoff the first 10-20% of the wort, it will be cloudy with some chunks. This is recirculated. The husks of the grain then form the filter bed, and the false bottom holds the husks back. Many people make the mistake of trying to make the false bottom do the filtering, which quickly clogs up.

Air flowing back up the runoff tube shouldn't stop the runoff. But many brewers do aim to have no splashing and the runoff tube full to avoid HSA.

Keep the sparge water at or just above the top of the grainbed.

Have a look at what other people use as false bottoms. Get some rice hulls and place a layer over your false bottom, about 4-cm layer should fix your problem.

Watch the sg of the last runnings, don't use any of the last wort with an sg of less than 1.010. Don't rely on temperature correction tables for hydrometers, crash cool your sample in a plastic bag in an ice bath and then do a reading.

If you have another very slow runoff, get a long serrated knife and make 4-6 cuts through the grainbed, almost to the false bottom. The top should resemble a noughts and crosses board. This will provide a path for the runoff to follow. As the runoff proceeds, the wort gets thinner and flows better.

 

[T.D.]

Based on what I do, I would collect that amount of wort in roughly half the time. I work on a rule of sparging at a rate of 1 litre every 1-2 mins (and usually go slower rather than faster just to be sure). You are pretty much doing it at a rate of 1L every 4 mins. "How to Brew" recommends 1 quart per minute (pretty much 1L per minute) but I found my efficiency suffered a bit at this rate, so I generally do it at the slower end of the range I mentioned above (ie 1L every 2 mins).

There is no real "too slow" rate, like there is a "too fast" rate. The only draw back of doing it slower is that it takes up more of your time. Doing it faster risks stuck sparges and low efficiency (persumably due to channeling in the grain bed).

 

[ibast]

I used to get a really slow sparge too.

One trick I learned was to hold the racking tube up (assuming it is flexible) so that it fills with wort. Then lower it into your bucket. this will get the air out and the wort wil syphon it'self.

You may then have the opposit problem of it sparging to quickly.

I think everyone has problems with this and they all come up with different solutions.

e.g. I don't use a false bottom, rather I have a mesh bag I line the brew pot with. It's the type they wrap hams in. I then put my long spoon down the side of the bag at sparge time, so I can move it (slightly and slowly) away from the pot outlet, it it gets stuck.

Good luck

 

[tangent]

Watch the sg of the last runnings, don't use any of the last wort with an sg of less than 1.010.

why's this POL?

 

[Jazman]

tanins

 

[warrenlw63]

am or should that be Monkey?

May pay to list your ingredients I think, you didn't use a percentage of adjuncts like flaked barley or oats? Sounds to me like you may have had a blockage somewhere. A false bottom can drain as quickly as you can open the tap.

When I fly sparged (batch now) I'd usually get the complete volume within 45 minutes for 44 litres in the boiler, using about 8kg of grain.

Did you turn the tap on fully right from the outset? If so there's a realistic chance you've compacted the grainbed to a degree. If you're crushing your own grain you may be crushing too fine.

Warren -

 

[tangent]

i don't understand, low sugar levels extract more tannins?
I thought everything is aok as long as i don't sparge too hot?

i batch sparge twice and everything seems to be going nicely.

 

[pint of lager]

In fly sparging, as the concentration of extracted sachaarides drops, the pH rises and there is more chance of tannins being extracted from the husks.

Towards the end of runoff, fly spargers usually monitor the sg. You can easily monitor the flavour by running off a sample into a coffee cup (larger thermal mass so the wort cools) and tasting it. Even though you may have stopped running off into the kettle, keep sparging and collecting till you taste the tannins, this way you know what flavour you don't want in the kettle. I have noted a change in the aroma of the runoff too.

Batch sparging is another matter. In theory, because the concentration of the sachaarides is much higher, you don't run the risk of tannin extraction compared to fly sparging.

Don't sparge too hot, as this also causes tannin extraction.

 

[Samwise Gamgee]

May pay to list your ingredients I think, you didn't use a percentage of adjuncts like flaked barley or oats? Sounds to me like you may have had a blockage somewhere. A false bottom can drain as quickly as you can open the tap.

No adjucts used warren, just cracked, malted grains (trad ale x 4kg, 250g wheat, 230g munich, 120g crystal and 75g chocolate)

Did you turn the tap on fully right from the outset? If so there's a realistic chance you've compacted the grainbed to a degree. If you're crushing your own grain you may be crushing too fine.

i only had the tap opened slightly at first for a slow run off, the after about 30 mins and not extracting much i opened a little more, then eventually opened completely.

I forgot to mention, i used racking tube with a GMK in-line filter.

The run out of the tap seemed to be relatively quick (by watching the movement of little bubbles) but then slowed down in the tube. The tubing would be full of wort for about half way then had air in the tube and slow runnings.

In regards to the crush, i don't crush myself so I can't really comment on that. I didn't really look at the crush either so i'm not sure if that was the cause.

Thanks to everyone for your advice!

P.S. yes you can call me Monkey :lol:

 

[warrenlw63]

Bingo!

My money's on the in-line filter. Get rid of it for mash runoff.

Warren -

 

[Samwise Gamgee]

hehehe

ahhhh $hite, i should've mentioned that in the original post h34r:

The filter doesn't build up with a lot of solids that would restrict a lot of flow, but any restriction is a restriction.

no filter next time and we'll see how it goes!

 

[pint of lager]

Who told you to filter the wort runoff with an inline filter? Get rid of it.

Runoff will be cloudy at the start with some chunks. Recirculate the first 10-20%, it will clear up.

 

[Samwise Gamgee]

no one told me to use it for that. I recirculate the first litre or so, then i'd use that for good measure but now seems to have ad an adverse effect.

off it goes!

 

[warrenlw63]

am

Even if your runoff appears clear. Don't be fooled. Over the course of 30 odd litres you'd be surprised how much fine stuff goes through to the boiler, not to mention a little plastic filter. Don't get concerned it will all precipitate out after the boil.

Warren -

 

[ibast]

No adjucts used warren, just cracked, malted grains (trad ale x 4kg, 250g wheat, 230g munich, 120g crystal and 75g chocolate)

I've had trouble with wheat in the past too.

The tubing would be full of wort for about half way then had air in the tube and slow runnings.

Yep this is what I use to get.

Try the "burping" technique of lifting the tube. It forces that bit of air back up through the grain bed. The wort then acts like a syphon, as I mentioned