Author Topic: Time Delay from Mash to Boil  (Read 4433 times)

Offline hokerer

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Re: Time Delay from Mash to Boil
« Reply #15 on: March 12, 2011, 12:29:27 PM »
::) doh!  Sorry, my head is clogged with a bad cold today - well that's my excuse anyway.  I was actually thinking that, conversion isn't stopped dead in its tracks until +170F, but IIRC, it's above that temp you start to get too much tannin extraction??

Tannin extraction depends on both temperature and pH.  That is, even if you let the temp get too high, tannin extraction won't be a problem unless the pH is also too high (>6.something, I can't remember exactly).  Most all the time, your mash pH is less than that so accidentally going too hot isn't a huge concern.
Joe

Offline brewsumore

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Re: Time Delay from Mash to Boil
« Reply #16 on: March 12, 2011, 01:13:50 PM »
It is pH above 6 you extract excessive phenols and tannins from the mash (Palmer pg. 159).

So I'm thinking that if you are planning to leave your mash runoff for 24 hrs before boiling, maybe you would want to take it to =/+170F, which would prevent further extraction during the following sparge, but would definitely shut off the conversion process. ???

Offline denny

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Re: Time Delay from Mash to Boil
« Reply #17 on: March 12, 2011, 02:35:33 PM »
It is pH above 6 you extract excessive phenols and tannins from the mash (Palmer pg. 159).

So I'm thinking that if you are planning to leave your mash runoff for 24 hrs before boiling, maybe you would want to take it to =/+170F, which would prevent further extraction during the following sparge, but would definitely shut off the conversion process. ???

It sounds like the OP is going to collect all the wort before leaving it overnight. 
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Offline brewsumore

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Re: Time Delay from Mash to Boil
« Reply #18 on: March 12, 2011, 02:38:55 PM »
I see, so if you are interested in killing off conversion processes, collect combined mash and sparge runoffs, and heat that to 170F prior to cooling, to protect your fermentability profile.   :)

Offline hokerer

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Re: Time Delay from Mash to Boil
« Reply #19 on: March 12, 2011, 02:43:34 PM »
I see, so if you are interested in killing off conversion processes, collect combined mash and sparge runoffs, and heat that to 170F prior to cooling, to protect your fermentability profile.   :)

Or do a real "mash out", that is, heat the mash grain bed to 170F for 15 minutes and then run it off and store it.
Joe

Offline denny

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Re: Time Delay from Mash to Boil
« Reply #20 on: March 12, 2011, 02:48:06 PM »
I see, so if you are interested in killing off conversion processes, collect combined mash and sparge runoffs, and heat that to 170F prior to cooling, to protect your fermentability profile.   :)

Or do a real "mash out", that is, heat the mash grain bed to 170F for 15 minutes and then run it off and store it.

That won't pasteurize your wort, though.  If you heat it to 170 in the kettle and hold it for 10 min., theoretically you'll kill off wort spoiling bacteria.
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Offline Will's Swill

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Re: Time Delay from Mash to Boil
« Reply #21 on: March 12, 2011, 07:09:37 PM »

I'll bet it did. Were you using the iodine test to decide if it had converted?

Yep.  After an hour the iodine instantly turned black.  It gradually took longer to turn black until after six hours it took maybe 30 seconds to a minute.  I called that good enough.  I was using grain that was well over a year old (bought two fifty # bags of 2 row becuase the price was great, but didn't quite get through the second...), and a lot of popcorn as an adjunct.  Not a good combination I guess.
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Offline hokerer

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Re: Time Delay from Mash to Boil
« Reply #22 on: March 12, 2011, 09:21:20 PM »
That won't pasteurize your wort, though.  If you heat it to 170 in the kettle and hold it for 10 min., theoretically you'll kill off wort spoiling bacteria.

Good point, I was only focused on stopping the enzymes.  Completely missed the spoilage bit.
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Offline Will's Swill

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Re: Time Delay from Mash to Boil
« Reply #23 on: March 14, 2011, 09:09:20 PM »
OK, the resuts are in on my inadvertant test on the effects of an overnight delay between mash and boil.  My intent on brew day was to split the runnings from a single mash into two boils.  ("Why?" you may ask.  I was intending to test for any effect on taste when using a counterflow chiller vs. an immersion chiller as the result of a conversation on another forum.  There was no intent to wait overnight for one boil at the outset, but the brew day was a disaster...)  I don't perform a mash out when I brew and I did not heat the wort beyond the mash temp before putting up for the night, nor was the wort insulated.  I essentially used my keggle as a lauter grant to accumulate the runnings, mixed thoroughly, ran off half into another smaller kettle, and then executed one boil immediately to make Hop You Now.  I covered the keggle with the remaining wort with Saran Wrap and moved it inside overnight.  The next morning I performed the exact same boil to make Hop You Later.

Some vital stats:

Hop You Now - O.G. 1.062, F.G. 1.008 (CFC if you care)
Hop You Later - O.G. 1.059, F.G. 1.009 (IC)

So I don't think fermentability was affected by the overnight delay.  While bottling yesterday, I took samples of both and my wife poured me a double-blind triangle test.  I was able to correctly identify both the two samples that were the same and which batch they came from, but...  Hop You Now was noticeably darker than Hop You Later, so I'm pretty sure that that biased my result.  So I did another double-blind triangle test but this time in opaque glasses (does that make this triple-blind?).  In this arrangement I was unable to separate the two batches.

Unfortunately, I have no idea why one would be darker than the other.  Maybe something to do with settling overnight, but my keggle has a dip tube that leaves almost nothing behind when I drain it, so I wouldn't think so.
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Offline euge

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Re: Time Delay from Mash to Boil
« Reply #24 on: March 14, 2011, 11:06:02 PM »
The darkening might be oxidation. Anyway, it's worth another for repeatability- right?

Sometimes I'll leave wort to chill in a water bath overnight. So far it's been no problem. To me it seem that if you turn the flame off, and put the lid on it's gonna be sterile in there until it is opened again. At least for our purposes a couple days.

Thanks for the inadvertent experiment. So there was no difference due to chilling methods? Maybe this is the source of the darkening? WAG.
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Offline hokerer

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Re: Time Delay from Mash to Boil
« Reply #25 on: March 15, 2011, 06:14:26 AM »
Some vital stats:

Hop You Now - O.G. 1.062, F.G. 1.008 (CFC if you care)
Hop You Later - O.G. 1.059, F.G. 1.009 (IC)

It sounds like you ran off into one container, mixed it well, and then split it in two?  How then did you end up with two different OG readings?  I'm confused.
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Offline Will's Swill

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Re: Time Delay from Mash to Boil
« Reply #26 on: March 15, 2011, 03:45:05 PM »
Darkening due to oxidation may be possible, or maybe it is chilling method (I kinda doubt either, though).  I did aerate Hop You Now the night I boiled it by pouring it back and forth from a carboy to a bucket, but I didn't pitch the yeast.  I wanted to pitch the yeast into both batches at the same time and temperature.


It sounds like you ran off into one container, mixed it well, and then split it in two?  How then did you end up with two different OG readings?  I'm confused.

Right, I suspect it was not mixed as well as I would have liked, and I got some density stratification in the lauter grant (keggle).  If so, the first batch that I ran off from the bottom of the container - Hop You Now - would be expected to have a higher gravity, though they are pretty close.

The implication here is that there's no taste difference between the IC chilling and the CFC chilling either, but if I did adversely effect Hop You Now through oxidation, the detrimental flavors may not have come out yet.  Time will tell...
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Offline mdkbrew

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Re: Time Delay from Mash to Boil
« Reply #27 on: March 16, 2011, 01:04:25 PM »
Thanks everyone for your input.  It certainly seems some experimentation is in order.  Cheers!

Offline Will's Swill

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Re: Time Delay from Mash to Boil
« Reply #28 on: April 25, 2011, 05:15:16 PM »
So I may have spoken too soon about there being no difference between Hop You Now and Hop You Later.  I've been drinking them for a while now and haven't detected a difference except for more haze in Hop You Later.  But...

A brewing buddy of mine who has moved out of state was back in town this weekend.  So naturally we got together Saturday night and drank some homebrew.  Just for fun I set up a couple of double-blind triangle tests.  One was Hop You Now v. Hop You Later in opaque glasses (the other was US-05 v. WB-06 in a pumpkin wheat).  To my surprise, two out of three tasters could separate the two lagers.  Now remember that I originally had brewed these as a side-by-side comparison of the effects of chilling technique on taste, CFC v. IC.  If there was a difference at all, I expected the IC to have less DMS and more hop aroma.  However, though they tasted very similar, the CFC beer (Hop You Now) had a rounder, more pleasant bitterness, and a more floral aroma.  In addition, the IC beer (Hop You Later) had what was described as a very subtle sourness.  I think perhaps it picked that up in the overnight wait for the boil, as I can't imagine that this was caused by the chilling technique.

I'll have to repeat the experiment to separate out the effects of the chilling technique from the overnight wait prior to boil.
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