Cold Malt Extraction

[ChristinaS1]

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.

[porschemad911]

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 

[ChristinaS1]

@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.

[porschemad911]

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 

[porschemad911]

Next experimental batch is under way, a pale ale which will be hopped with Dr. Rudi, Mosaic and Simcoe.

At around 6 this morning I added 3kg Joe White Signature ale malt, 75g Simpson's Light Crystal malt and 75g Simpson's Medium Crystal malt to 17l cold tap water and a 1.5l ice brick.

Normally this would give me 11l of 1.050 OG wort in the fermenter, so see how this goes. I'm curious to see what temp it will be at by the time I get around to running off tonight. I'll be doing a 20 min rest at 68C after run-off, then a 60 min hop boil, then no-chill in the kettle and will be fermenting with BRY-97. 

Cheers, 

John 

[porschemad911]

Well that is closer to the mark at least. Ended up at 1.028 OG and tasting good. Very clear wort despite the short conversion rest (aided by Whirlfloc I guess). The 'mash' run-off was brilliant this time thanks to the coarser crush. 

So how to get the OG even lower? Three thoughts:

• Maybe the steep temp was still too high (11C). I'll use an extra ice brick to bring it down further. 
• Maybe I don't need a conversion rest at all, and enough conversion will happen on the relatively slow ramp to a boil (given that I'm on a gas stovetop). 
• Maybe I just need to use less malt.

Interesting though! The process is very convenient, so if the beer still tastes good and comes in at a lower ABV then it's a win all round. 

Cheers, 

John 

Edited October 12, 2019 by porschemad911

[ChristinaS1]

@porschemad911 Hey John. Neat that you are trying this again.  Thanks for sharing your process.

If you work out all of the kinks and perfect this method, that would be great. All the reports I have read online of people doing this, they only tried it one or two times and then went back to regular brewing. I get the feeling that even at Briess they did not try it out that often. But since you like low ABV beer, you may have more incentive than most to keep refining the process.

Cheers,

Christina.

[porschemad911]

Hopefully I can get it down pat because time-wise the split brew day process is perfect for me, and I am only interested in flavour, not alcohol. I suspect it will take quite a few iterations to get right, particularly adjusting the hopping to suit low ABV versions of different styles. 

Cheers, 

John 

[porschemad911]

I brewed up my third experimental batch on Tuesday night. Recipe below ... similar to the last pale ale but lower hopping rates. No mash rest this time, but I brought the runnings up to 75C fairly slowly, then more quickly to a boil. Skipping the mash rest took the OG in the right direction, down to 1.025 (vs 1.028 with the same grain bill last batch).

Stats
11l fermenter volume
25 IBU
18 EBC
1.025 OG

Malt
3kg Joe White Signature malt
75g Simpson's Medium crystal malt
75g Simpson's Light crystal malt

Hops
7g Dr Rudi at FWH
10g Dr Rudi at flameout (15 min steep)
10g Mosaic at flameout (15 min steep)
10g Dr Rudi dry hop
10g Mosaic dry hop

Yeast
BRY-97 slurry

Process

• cold-steeped malt in my cooler mash tun with 3l ice brick - was at 9C after 13 - 14 hours
• no sparge, runnings raised slowly to 75C over moderate heat, then high heat to a boil
• 60 min boil, then 15 min flameout hop-stand
• no-chill in kettle

I plan to brew basically the same recipe next time (with hopping tweaks as needed), just altering one step in the process. Next time I will just bring it to a boil as quickly as I can, which I hypothesize will lower the OG a few points more. Baby steps ... trying to avoid a bunch of unconverted starch in the beer.

To report on the previous pale ale batch ... it is laughably good considering the experimental nature and low ABV ... crystal clear, good body, mouthfeel and head retention, plenty of hop flavour and aroma. I just want to see how it goes with a little less bitterness (25 IBU) and lower late / dry hopping rates (2g/l).

Cheers,

John

[ChristinaS1]

Keep up the good work John. This is a very interesting process. I love reading about it.

Having made a third batch, you are probably the world's expert on this method now. I have not seen any reports of anyone trying it more than twice. 

If you are happy with this batch, why not try entering a sample in a competition?

Cheers,

Christina.

Edited November 14, 2019 by ChristinaS1

[porschemad911]

I brewed up the 4th experiment last night, same recipe as #3 but ramping to a boil as quickly as my stove would allow, with no mash rest. Seems to have worked well, producing nice clear wort again.

I'll confirm once sampling the finished beer, but I think this process is a winner. Next to try some different styles... Saison will be up first. 

Cheers, 

John