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porschemad911

Cold Malt Extraction

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3 hours ago, porschemad911 said:

Thank you very much for passing that on! For my next attempt I will try heating the runnings to 67C, resting for 20 mins, then heating to a boil.

Did Dan mention anything about the overnight steep time / temp? I did around 14 hours at 10 - 11C. Perhaps this was too long and too warm. I can use a big block of ice to drop the temp right down if need be, although shortening the time is tricky. 

I dry hopped the beer today. It had dropped bright already so I will give it another week then bottle. Despite the high ABV (around 4.3% bottle conditioned) it smells and tastes great. 

Cheers, 

John 

Hi John,

My pleasure. I was curious myself. 🙂

I did not ask Dan about the overnight steep but the abstract says to conduct passive cold extraction, "at refrigeration temperature, for 8+ hours." I understand that to mean 8 hours is a minimum, with 24 hours being the maximum (time at which they did their chemical analysis). 

No doubt the point of refrigeration temperatures is to inhibit microbial growth. I agree that your steep might have been too long and too warm, but if it is tasting great you might have gotten away with it. 👍 I will be very interested to hear how you find it compares to regular mashing once it is ready to drink.

I guess one downside of this method is trying to fit a full sized mash into a fridge. It might be better suited to smaller batches sizes, such as what you are making....I am toying with the idea of cold mashing 1kg of Maris Otter overnight and using the cold extracted wort to sparge my regular (hot) partial mash the next day.  That way my boil volume remains the same and I don't exceed the capacity of my mash tun or kettle, but I get more grain into my brew.  But it does sound like a lot more work than increasing the size of my partial mash by 25%, from 1.25kg to 1.5kg, which to be honest my mash tun and kettle can probably still handle. The flavour increase from cold extracting 1kg of Maris Otter vs hot mashing 250gm would have to be pretty big to make it worthwhile. 

Cheers,

Christina.

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5 hours ago, ChristinaS1 said:

I guess one downside of this method is trying to fit a full sized mash into a fridge.

Yes, even with my small batch size there's no way I'm fitting that into our fridge at home. Ice and insulation would be a good alternative. If I had been more prepared with ice I could have gone right down to fridge temps.

5 hours ago, ChristinaS1 said:

But it does sound like a lot more work than increasing the size of my partial mash by 25%, from 1.25kg to 1.5kg, which to be honest my mash tun and kettle can probably still handle. 

I would say that if you're already doing a mash, just add the grain into there if your equipment can handle the small volume increase. I don't think a cold extraction on the side as well is worth the extra work.

So... A few things I will try for next time:

  • Coarser crush
  • More ice to keep the steep temp way down low
  • 20 min mash rest on the way to the boil

I'll see how those go. I think that I'll stick to a 1.050 OG grain bill for another test before going into Doppelbock territory - maybe a Marzen. 

If my OG is still way too high, then another factor might be efficiency differences. Perhaps the amount of grain I normally would use for a 1.050 OG beer at my target volumes is more than what Briess would. So next step after that would be to cut down on the amount of grain.

But I do think cutting down the mash rest will go a long way. I have noticed a significant difference in SG after mashing for 30, 60 and 90 mins respectively, hence why I usually do 90 min mashes. I'm hesitant to cut that step out completely because I don't want unconverted starch in the beer, but have heard from many sources that 20 mins is more than enough time for full conversion. 

Cheers, 

John 

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@porschemad911 and @BlackSands

BlackSands mentioned using Beano / Alpha Glactosidase in another thread, to clear a hazy beer. I have read that commercial breweries are experimenting with enzymes to get more gravity points from their mash and reduce their costs.

While your aim, John, is to create a low alcohol brew, it just occurred to me that partial mashers could go the opposite way and try to wring more gravity points from their grain by cold mashing with Beano. So the process would be:

1.) Using a 4L/kg ratrio of water to grain, measure water into kettle. Water should be roughly room temperature, to kick start enzyme activity.

2.) Crush Beano tablet (s) between two spoons and stir into water. I am guessing 1 tablet per kilo would be a reasonable dose, but more might be better, as it will have to work at sub-optimal temperature. 

3) Using a grain bag, add grain to kettle. Stir, and stick in fridge x 24 hours. This would be the safest approach from an infection control perspective.

Another (possibly more effective) option would be to start the mash at 10C x 14 hours, as John did,  since he got plenty gravity points from the grain, even without Beano, and did not have any trouble with lacto infection. It would then be possible to keep the mash out of the kitchen fridge....John, I am guessing your higher mash temp accounts for your higher than expected gravity.

4.) Next lift grain bag into a sieve and drain wort into kettle. Using 2-3L/kg pour hot tap water slowly over gain, or use a separate vessel to immerse the grain for 10 minutes. Wearing rubber gloves, squeeze the bag.

5.) Bring wort up to mash temp and rest for 20 minutes.

6.) Finally, turn up the dial and boil as per usual. This would denature all enzymes, including the Beano.

It would take some experimentation to see how well Beano enhanced cold malt extraction would work: the gravity could fall short of normal hot mashing, match it, or exceed it. I might have to try making two small batches, side-by-side, using John's 10C x 14 hour method, one with Beano and one without. If I do, I will certainly post about it here.

Cheers,

Christina.

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On 8/13/2019 at 9:09 AM, ChristinaS1 said:

John, I am guessing your higher mash temp accounts for your higher than expected gravity.

I'm not so sure about this. My reading shows people doing it at lowish room temp achieving low gravities. I suspect it was either that the steep time was too long or the mash rest time was too long. 

For my next batch, I'm going to keep the steep time the same and shorten the mash rest step in an attempt to figure out which it was.

Cheers, 

John 

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