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Sparging: Large volume of low gravity wort

eddiewould

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Hey guys,

My setup is roughly as follows:

Rubbermaid 10 gallon cooler w/ false bottom, 5 gallon brew pot. I have a somewhat hacky fly-sprage setup whereby I fill my fermenter bucket with sparge water (say, 75c). I put it high up on a table. Connected to the fermenter bucket tap is a silicone pipe made into a ring with a T connector, there are lots of little holes in the pipe to allow water to dribble out. The ring is suspended above my mash tun, dribbling onto the top of my grain-bed (at a rate of about half a litre per minute). I try and keep an inch of water above my grainbed.

I take gravity readings of the runnings at regular intervals (pipette a small volume onto a refractometer).
It starts off very slightly below my OG, then increases to slightly above my OG, then tapers down from there. Problem is it gets down lowish quite quickly - I end up drawing a lot of wort at around 1.015. I'd normally stop at 1.010 however I gave up yesterday. The wort drawn does not taste astringent.

To try and summarize my problem: I'm currently ending up with a larger volume of lower gravity wort. So to hit the pre-boil gravity the recipe calls for, I end up doing a longer boil (say an extra 30-45 minutes), before doing any hop additions. From there, everything is fine. Is there something I can change to my process/equipment to end up with a smaller volume of higher gravity wort? So that I can avoid the extra boiling to hit the pre-boil gravity?

Hopefully this makes sense to someone.


Eddie
 
Hi Eddiewould,

What about your sparge temperature and the lenght sparge water is travelling through your grain in your set up?

In the beginning I ran in the same problem as you are describing and started looking for a practical solution.

The efficiency is determined by a lot of parameters (temperature and temperature control, pre-boil volume, grist size, grain weight, wort absorption ratio of the grain, lauter tun dead space, relative size of the runoffs and number of sparges etc.). Many of these parameters are set by the recipe (grain weight) and process/set up (absorption ratio and lauter tun dead space) while others can be changed (f.e. pre-boil volume and the number of sparges).

In my case I found out that I had a need for a more stable sparging temperature (76-77c) in combination with a change in my sparge set up by creating a much longer distance for the sparge water to travel through the grain.
In addition I run one extra sparge. These changes helped much in my case.

In your case your problem also could be caused already in the mashing stage having a low conversion efficiency (not enough starch was converted during the mash). Perhaps you could also focus on that part.

I copied a link to a very interesting brewing site regarding sparging for you here (Braukaiser):

http://braukaiser.com/wiki/index.php?title=Batch_Sparging_Analysis

Good luck and regards,
Slurk
 
Sparge temperature for the brew I did on Saturday was about 75c. Although it probably cooled a bit during the sparge, so may have been 70c or so by the time I finished. I could try putting a head-pad under my sparge water (might help a bit?)

I'm not really sure what you mean by length of sparge water. There's basically a silicone pipe shaped into a ring hovering above my grainbed, the sparge water drips out of little holes in the ring onto the top of the grainbed at a rate of about 0.5L/min

From there, the water just goes through the grain (I guess about 30-40cm high)? and comes out the bottom of the mash tun. When you said you started performing an extra sparge, what do you mean? (I'm doing a continuous fly sparge, are you batch sparging)?

Thanks for the reply
Eddie

 
What were your mash conditions?  Temp? pH? Time, eg 60 or 90 min?  Im also having efficiency issues and could use advice.  Ive lengthened my mash time and increased sparge temp/length (slowed flow rate) with positive results.
 
Mashed at 66c (hit temp spot on), held for 50 mins, mash out at 75c 10 mins. No idea about pH.

To reiterate - I don't think I'm having problems with efficiency per-se: I'm getting "enough" sugar out of my grain without extracting noticeable (by me) tanins. I'm hitting around 75% efficiency which I'm happy with.

I'd just like to avoid having to boil it down first. I might try a slower sparge and try and keep the water temperature more consistent.
 
Hi Eddiewould,

- I am using batch sparge
- "creating a much longer distance for the sparge water to travel through the grain" = creating more depth of grain bed

Regards,
Slurk
 
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