High Gravity Mash/Sparge Issues - Comments and Suggestions Please!

Lately, my brewing buddy and I have been making high gravity (Belgian) beer. On Sunday, we mashed 14 pounds of pilsener malt in 21 quarts of water, which comes out to 1.5 quarts/pound. We seem to have efficiency isses when doing this. I think the problem arises from too much water in the mash, which takes away from sparge water volume, so some sugars get left behind. We're trying to mash for attenuation, so we mash with lots of water at lower temperatures. We recycle until the runnings are clear, then drain the wort off of the grain until we have between a half-inch and an inch of wort above the grain bed, and then we begin sparging. For a 5 gallon batch, we didn't need too much sparge water before we obtained our pre-boil target volume. With the pils malt and 2 lbs of candy sugar, our OG turned out to be 1.084 which doesn't sound too bad until you realize that we were shooting for 1.096 for 75% efficiency. Our efficiency was 63%, and we'd like to improve. Any ideas, or can anybody point out a major flaw in our procedure? Thanks in advance!

If you use a ratio of 1 qt/lb there will be more room for sparge water. Also, be prepared to sparge with more water than normal to rinse the grain better. Then increase the boil time to bring the batch back to the normal size.

That sounds good. We'll definitely try 1 quart/gallon next time. I wonder how this will affect attenuation ability. Does everyone think it'll be thin enough for a more attenuable mash?

Yes, the concentrated mash will incerase the density of enzymes and can speed up the conversion. Just make sure you stir it well to avoid any dry spots and be sure to double check that your temp has setteled at the target temp. Remember that less strike water will require a higher temp to attain your desired mash temp due to the heat sink of the grain.

Steve973 - What batch volume are you brewing? By my mash calculations you could get a maximum gravity of 1.097 from 14 lbs of Pilsener malt in a 19 litre / 5 U S Gal batch. 1.084 /1.097 is about 86% by my calculations. I assume that you are fly sparging; how fast are you sparging and how much wort volume are you collecting for the boil?

Alvin said:

Steve973 - What batch volume are you brewing? By my mash calculations you could get a maximum gravity of 1.097 from 14 lbs of Pilsener malt in a 19 litre / 5 U S Gal batch. 1.084 /1.097 is about 86% by my calculations. I assume that you are fly sparging; how fast are you sparging and how much wort volume are you collecting for the boil?

Click to expand...

I agree with Alvin, your mash extraction will vary a lot depending on how fast you drain/sparge. Changing the water to grist ratio to a thicker mash will affect the fermentables so I wouldn't change that necessarily. You could try fly sparging very slowly (less than 1qt per minute) or drain the MT completely, refill with hot water to the top of the grain bed to refloat it, and restart your sparge.

A good extraction of 30pts/lb of grain (around 90% eff.) is quite attainable. So with your 14 lbs of grain, you would expect 5 gallons of 1.084 wort, before even adding the sugar.

Seb

steve, try just recirculating for 20 minutes, then start draining to the mash tun and sparging w/ 170-175 degree water. do the recirculation and sparge very slow. a sparge for a big beer should take 90 - 120 minutes. make sure you hit your saccharification rest temp, and mix the grain and stike water well to eliminate any dough balls.
or, you could follow janx's advice. if your efficiency is low, add more grain! :~)

Thanks for the replies, everyone. We were brewing a 5 gallon batch in one of the 10 gallon yellow rubbermaid coolers with a bazooka tube in the bottom. I assume that we recirculated for about ten minutes before starting to drain the wort. I don't consider that part "sparging" because we're not adding clear hot water to the top at this point, just draining it down until it nears the top of the grain bed. Then we sparged. I don't know how long we could try to sparge a gallon or two, but we'll try stretching it out next time. With so much water in the mash, it doesn't feel like we could get a proper sparge. Any suggestions for that? We gathered about 6.5 gallons before the boil.

By the way, Alvin, we obtained 1.084 only after adding the candy sugar, so our efficiency is bad. I might try using a larger amount of sparge water next time, and use our old (smaller) mash cooler to hold the water so it stays hotter...

Is there a benefit to recycling the wort back through the grain bed after the sparge? How about heating the wort up to 170 F and then recycling it through? Would that increase extraction efficiency?

yes, it helps set the grain bed for sparging, plus it uses the grain bed as a natural filter. i recirculate for about 20 minutes prior to sparging. i very seldom do a mash out @ 168 degrees.....

Our beer went from 1.084 to 1.040 when we transferred it to secondary. This was after ten days of fermentation. It is slowing down but still going. Do you think there's hope for getting it down to at least 1.020 or better? It's in a room that's cooler than the rest of the house, so that might slow it down, but probably isn't any lower than 68 degrees.

I need to know what the temp of your water was when mashing in. The common misconception is that you need to mash at a temp of 152 to 157, this is where you lose allot of your efficiency. If your looking to get a high gravity beer then mash in so that the temp after you put your grains in, is about 149 degrees for 90 minutes. Remember you cannot over convert your mash and you will yield a higher amount of fermentables this way. happy brewing

Semper Fi!

sdent said:

Is there a benefit to recycling the wort back through the grain bed after the sparge? How about heating the wort up to 170 F and then recycling it through? Would that increase extraction efficiency?

Click to expand...

What will work to some extent is buy some amalyse enzyme add it to your mash and you dont have to worry about being undercoverted, Cheers

usmcruz said:

I need to know what the temp of your water was when mashing in. The common misconception is that you need to mash at a temp of 152 to 157, this is where you lose allot of your efficiency.

Click to expand...

I got a lot of my info from a book by Stan Hyeronymous called "Brew Like a Monk" and it suggested mashing the grains at 146. We mashed for 2 hours, then sparged.

Semper Fi!!!

Steve973 said:

I got a lot of my info from a book by Stan Hyeronymous called "Brew Like a Monk" and it suggested mashing the grains at 146. We mashed for 2 hours, then sparged.

Click to expand...

146 Degrees is ok, the cooler part of the house might make the difference too. The only thing is that if the yeast was suppose to ferment lower than 1.020 and you prime and bottle condition in a warmer area you might get over carbonation going on. Move it to the warmer part of the house, ester's and phenols were more likely to develop at the start and through active fermentation not now. Now your just trying to see if thats all it going to ferment to. If it does start up again, i mean even one bubble a minute i would wait to bottle until no activity. cheers

I'm probably also going to re-yeast for the secondary. It certainly cannot hurt to have more fresh yeast, especially in a high gravity brew. Does anybody recommend re-oxygenating with an O2 tank for this? And yes, I'm also going to re-yeast at bottling time.

Steve973 said:

I'm probably also going to re-yeast for the secondary. It certainly cannot hurt to have more fresh yeast, especially in a high gravity brew. Does anybody recommend re-oxygenating with an O2 tank for this? And yes, I'm also going to re-yeast at bottling time.

Click to expand...

Adding oxygen to the fermenter for the yeast would be a bad idea. You will have some oxidized beer on your hands, but as for the yeast, if you make a starter you can hit the valve and oxygenate the wort for your starter and only the starter. After no more activity in your starter then pitch. I you pitch the starter too soon, the dissolved oxygen in your starter will cause flavor problems with your brew. If it were me i would wait, and not use oxygen, but splash the wort around before making your starter so as to not over oxygenate with the oxygen.

Isn't the biggest concern with oxidation while the wort is hot? Some yeast companies recommend oxygenation during each transfer.

Steve973 said:

Isn't the biggest concern with oxidation while the wort is hot? Some yeast companies recommend oxygenation during each transfer.

Click to expand...

the only time you want to introduce 02 to the beer/wort is after cooling, prior to pitching. any time later and you'll get funky off-flavors.....

The oxidation that can occur in hot wort and the oxidation of the fermented ale are two different problems. More yeast = good, more O2 = bad.

Since you are setup for recirculation, why not try batch sparging next time? I drain the first run, add more water, stir gently and recirculate until the bed is set again.

I've rarely been able to get a 1.090 wort down below 1.025, even with a high gravity yeast in the secondary.

Steve973 said:

Isn't the biggest concern with oxidation while the wort is hot? Some yeast companies recommend oxygenation during each transfer.

Click to expand...

You can aerate any time within the forst 24 hours of initial yeast pitch in. 14hrs is an optimal time.
After 24 hrs the yeast no longer needs the O2 and adding it will result in Oxidation.

Aerate your starter as said previously.

If I read your post right I believe you're using a bazooka tube in the mash tun, correct? This might be a problem. They can and will channel. Now, if you're batch sparging and you stir the mash gently after adding the sparge and then proceed to recirculate and then drain into the kettle then this probably is not a problem. However, if you plan to fly sparge then I'd suggest you construct a copper manifold and use that bazooka tube in the kettle instead.

As for your efficiency I'll bet it'll noticeably improve if you fly sparge.. it'll also get better the slower you sparge. I've hit 31 points on a 1.063 OG 5.25 gal batch with a real slow fly sparge (90 min).

The other possibility is simply that you have an incomplete starch conversion. A thin mash will spread the enzymes out a bit more and starch conversion will take longer. As someone else very wisely said, you can't over mash. While 1.5 qts per lb is not remarkably thin I'd say extend the mash to 90 min just to be safe.

If all else fails then just sparge that sucker as slow and long as you can (stop if SG is 1.008 or less).. then boil that thing for 30 minutes before you start the hop additions to get it back down to a manageable volume.