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### Messages - jc24

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1
##### General Homebrew Discussion / Re: One for the physics gurus...
« on: May 16, 2018, 10:51:13 PM »
Are you one of those people who make up math questions?
Haha definitely not, but the OP does sound far too similar to an exam question for my liking!

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##### General Homebrew Discussion / Re: One for the physics gurus...
« on: May 16, 2018, 10:49:55 PM »
In reality there are way too many factors (air currents, humidity, material, geometry/wall thickness) to get an answer here, plus we'd have to take an indefinite integral while I'm on still on my first cup of coffee, but we can go all Fermi approximation on it. Short answer, to get to 2°F above ambient will take a very long time.

Desired heat transfer we do know exactly: 6.6 gal * 3.8 L/gal * 1.1 kg/L * 11°F * 1.8°C/°F * 4.2 kJ/kg°C = 2300 kJ

Newton's law of heat transfer to keep things simple: Q' = hA∆T. Figure a best-guess of 5 W/m^2K and 12"x 13.5" WxD gives hA = 1.6 W/K. Our average ∆T is 7.5°F = 4.2°C so Q' = 6.7 W and 2,300,000 J / 6.7 W = ~95 hours. Assuming constant flux is going to be over by quite a bit due to the long tail, so approximate it as 95*e^-1 = 35 hours.

But as Dave points out you don't need to exponentially decay all the way out to the exact target temperature, so in reality you'll be within a degree or so after maybe 24 hours.
Wow, thanks for taking the time to post this!

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##### General Homebrew Discussion / Re: One for the physics gurus...
« on: May 15, 2018, 12:20:43 PM »
6 hours enough?

4
##### General Homebrew Discussion / One for the physics gurus...
« on: May 15, 2018, 10:56:27 AM »
How long will it take for 6.6G of 1.102 wort at 79°F to cool to 68°F when sitting in an 8.5G plastic cylindrical fermenter in an ambient temperature of 66°F?

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##### All Grain Brewing / Re: Water treatment for reiterated mash
« on: April 25, 2018, 11:00:25 PM »
Best in mind that you may also be able to split the two grain bills into the initial one containing all the dark malts etc and the second one with just base malts in (dependant upon your grist).
I’m tempted with this but with 2.2lbs specialty malt, I’m wondering if my yield from mash 1 would be too low if I added it all at the start? Total grain bill is:
14.1lbs Maris Otter
1.9lbs Malted Wheat
2.2lbs Roasted Barley
2.2lbs Chocolate Malt
0.7lbd Crystal 120

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6
##### All Grain Brewing / Re: Water treatment for reiterated mash
« on: April 25, 2018, 10:55:38 PM »
The 477 ppm bicarb seems a bit high, but I'm guessing this is a high gravity wort.

Assuming you are working with the free version of Bru'n Water, the actual ion concentrations will be lower than the mashing concentrations that I think you're showing. That should help alleviate the concerns with Ca and HC03
Yes I’m using Bru’n Water and yes to the high gravity - OG = 1.100, 2.2lbs each of Roasted Barley and Chocolate Malt so yep, high bicarb!

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7
##### All Grain Brewing / Re: Water treatment for reiterated mash
« on: April 25, 2018, 12:41:13 PM »
Thanks for the quick reply. OK I think I'll forget about sparging with wort, and sparge with water as normal. I'll also add the Gypsum at the start. So it will now look like this:

1. Mash half the grain bill as per usual at 149°F for 60mins, treating the water as per usual for that volume (in this case it will be 4.6 gallons).

2. Sparge the first mash with enough treated RO water to reach 4.6G of wort, ready for the 2nd mash.

3. Add the 2nd half of the grain bill, mash at 149 for 120mins.

4. Sparge with treated RO water to reach full pre-boil volume.

By the way, here is my estimated profile - Ca seems a little high (I'm using Pickling Lime to raise RA), but I'm thinking it should be OK?

Estimated Profile
Ca = 157
Mg = 6
Na = 36
SO4 = 36
Cl = 46
Bicarbonate = 477

Estimated mash pH: 5.51

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##### All Grain Brewing / Water treatment for reiterated mash
« on: April 25, 2018, 11:41:42 AM »
Hoping Martin will chime in here...

I will be brewing a fairly standard RIS soon, but, due to the limitations of my system (Grainfather), I'll have to do a reiterated mash, but I'm wondering how best to treat my water for each step? I start with 100% RO water. My plan is this - keen to hear thoughts/suggestions (and yes, I know I could just add extract and do one mash, but I want to give this a go!):

1. Mash exactly half the grain bill as per usual at 149°F for 60mins, treating the water as per usual for that volume (in this case it will be 4.6 gallons) but leave out the Gypsum and CaCl2 additions as I'll be needing to raise the RA of the mash.

2. Sparge the first mash with pure RO water to reach full pre-boil volume.

3. Pump off wort into a separate vessel that I'll use for the 2nd sparge, until I'm left with 4.6 gallons of wort in the mash tun for the 2nd mash.

4. Add the 2nd half of the grain bill, mash at 149 for 120mins.

5. Sparge using the wort collected in step 3 above.

9
##### General Homebrew Discussion / Oak chips & fermentation
« on: April 14, 2018, 03:59:34 AM »
I am planning to brew a Foreign Extra Stout and want to add 1.7oz medium toast French Oak cubes (6.3 gallon batch). In order to try and minimise oxidisation and risk of infection, I'd love to avoid transferring to a secondary fermenter. What are the draw-backs to adding the oak cubes at the very start of fermentation, ie. when I pitch the yeast, and just leaving it for 3 or 4 weeks? I know that, theoretically, there is risk of off-flavours developing from the trub, but I'm not convinced :-) Anyone had real-world experience that can advise?

10
##### General Homebrew Discussion / Adding cucumber
« on: January 13, 2018, 04:17:17 AM »
I’m brewing a cucumber Saison and am wondering if I should add the cucumber to the primary (post-primary fermentation) and leave them in for a couple of weeks, or if it’s best to transfer to a secondary vessel and leave the cucumber in for longer? Would much prefer first option :-)

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11
##### All Grain Brewing / Bitterness in IPAs
« on: January 06, 2018, 10:50:47 PM »
Thank you! I have recently only been doing 30min boils with 15min and less hop additions so will try 60mins with a solid American hop. My sulphate levels are always at around 300ppm for IPAs so I think I’m good there.

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12
##### All Grain Brewing / Re: Mash pH way off
« on: January 06, 2018, 10:46:28 PM »
firstly, my mash efficiency was quite a lot higher than usual, and secondly, both beers have been slower than usual to ferment and seem to have stalled at 1.020. Is this what we would expect from a very low mash pH?

That is not my experience. I find that a lower mashing pH tends to produce a wort that is thinner and more fermentable. That suggests that the beer should ferment well and end with a lower than expected gravity.
Thank you! Haven’t been able to borrow a reliable pH meter yet - will keep trying!

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13
##### All Grain Brewing / Bitterness in IPAs
« on: January 06, 2018, 02:33:38 PM »
I'm wondering how to get that slow moving bitterness that creeps up on you and bites you on the back end? In most of my IPAs the bitterness is quite upfront, but I'd like to know how to get that bitterness to be a little more delayed?

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##### All Grain Brewing / Re: Mash pH way off
« on: January 05, 2018, 11:01:02 PM »
With the last 2 brews I’ve done, I added lactic acid to hit the correct pH according to my meter, which means if Bru’n Water was correct and my meter was off, I’d have had a relatively acidic mash. I noticed 2things about these beers - firstly, my mash efficiency was quite a lot higher than usual, and secondly, both beers have been slower than usual to ferment and seem to have stalled at 1.020. Is this what we would expect from a very low mash pH? I brewed last night and decided to trust Bru’n Water and not add any lactic acid - my efficiency is right where it used to be and the airlock is bubbling away 9hrs after pitching. Does all this seem to point to a faulty pH meter?

I’m brewing again soon and should have a reliable meter to test with.

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##### All Grain Brewing / Re: Mash pH way off
« on: January 03, 2018, 01:09:49 AM »
Thank you for the replies everyone. I used 3 different base malts for the brews I mentioned - Simpson's Maris Otter, Barrett Burston's Pale Ale and Weyermann's Pilsner. I shall do a mini mash with distilled water as suggested and see what reading I get. I'll have to wait for a while though as I've run out of calibrating solutions - have ordered more so hopefully I'll be able to do this test soon.

And yes, the easiest thing to do would be to borrow someone else's reliable pH meter - I'll see what I can do!

Thanks again - I'll report back here once I've had a chance to follow up on your suggestions.

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