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Messages - a10t2

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Equipment and Software / Re: Kegerator setup
« on: October 09, 2015, 10:10:45 AM »
It's going to be really difficult to get a decent pour at 2 fl oz/sec. In a home setting I don't see any need to pour that quickly.

You'll need about 15 psig to carbonate to 2.5 vol, depending on temperature. -3 psi for the vertical run, -5 psi for the hardware, leaves ~7 psi for tubing drop. About 10 ft of 3/16" ID beverage line.

is it the rate or total volume that is important here?  and is that an hourly rate, or total?  I'm sorry I don't see that info in the write up?  Man that is quick boil off - i boil off about 2 gal an hour, 15gal starting BV.  But then again i guess it would be an even higher rate if starting at 8.

I backed that particular number out of the other information in the post: 30 min boil, 1 gal/hr evaporation, 5.5 gal final volume. It's proportional; somewhere around 5-10% evaporation is needed to achieve the desired boil off of DMS. The Siebel coursework recommends a minimum of 8%, just to give one example.

This is a great example of what Denny's been talking about: an important variable being misunderstood (attributed to time instead of evaporation) and then endlessly repeated. It isn't that the science is flawed, it just isn't a concern for systems using such powerful burners.

Yeast and Fermentation / Re: New starter procedure trial
« on: October 08, 2015, 09:22:00 AM »
In my opinion, a vortex is not really needed when the headspace has a constant supply of atmospheric oxygen. I stir my wort only to the degree necessary to keep the cells in suspension. That is more like the shaken technique that Mark recommends.

Same here.

I was doing a 75' boil on Pilsner malt "just to be safe". Haha. Now I know that I can whittle that down even more. :)

I do want to point out again that boil length is only going to be correlated to DMS volatilization for a given kettle setup. Marshall's kettle is able to reach 9% boil off in 30 min; if you're boiling off significantly less than that you may need to boil longer.

All Grain Brewing / Re: Fly Sparging Question Regarding Temperature
« on: October 07, 2015, 09:18:28 AM »
Personally, I would just do the mash rest (and that 60 min can include the vorlauf, by the way), then vorlauf and sparge with liquor at around 185°F. Otherwise you have to either start with a very thick mash, or dilute it so much during the mashout that efficiency will suffer.

All Grain Brewing / Re: New to all grain a few ?'s
« on: October 07, 2015, 09:02:38 AM »
I was telling him not to try to "fly sparge" on a dry grain bed.  you seem to be comparing no sparge with batch sparging.  in general yes, batch would be better than no sparge when it comes to efficiency.

My point was that we were forced to spray the sparge liquor onto the dry grain bed, then run it off without stirring.

All Grain Brewing / Re: New to all grain a few ?'s
« on: October 06, 2015, 07:56:01 PM »
not sure but I think you'd be better off at that point stirring it up.  I'd expect a dryish grain bed to channel like a mofo.

You might be better off, but from a practical standpoint it could be better to run dry. I worked on a small brewpub system that had the outlet of the mash tun only about a foot off the floor. Consequently, we had to pump from the tun to the kettle. Switching from no-sparge to what we called "Denny-sparging" took the efficiency in that brewhouse from ~70% to ~83%.

Yeast and Fermentation / Re: New starter procedure trial
« on: October 06, 2015, 07:25:10 PM »
I'll say that I have $9 invested in my stir plate ($6 of that is the bar), and would have no problem with giving it up. I'm looking forward to trying out Mark's technique once I get my current glut of pilot brewing over with.

For those of us who had statistics so long ago that there were no desktop computers, can you explain the symbol and the formula for this "statistical significance" (p less than .05, for example)?  Near as I can tell, it comes out to about half...which leads to Sean's question about what level is significant, whether statistically relevant or just cuz it means something that can be considered reasonably dependable to base conclusions upon.

I'll try…

The thing that makes a triangle test so statistically useful is that it's binary; each participant either picks correctly, or doesn't. It's a coin toss, and if you toss a coin enough times you can collect valid statistics about how likely you are to get various combinations of heads/tails. The probability that a given heads/tails combination will come up for a fair coin is the p-value. In this case we're saying that, for something not to be due to chance, there has to be only a 5% probability that it occurred by chance, and therefore a 95% probability of it being an actual result. In the case of a triangle test, we'd expect people to guess correctly about 1/3 of the time, and so, as you noted, once the numbers of correct responses gets to something more like 1/2, it becomes significant. Exactly what that fraction needs to be for it to be significant depends on the desired p-value.

This is called a binomial distribution, by the way, and isn't limited to equally weighted outcomes or true/false outcomes, they just make the math much easier.

Edit: In the hard sciences (or at least in my experience), p<0.05 is generally acceptable for publication of empirical data. p<0.01 is generally desirable and would be accepted for publication pretty much anywhere.

General Homebrew Discussion / Re: First time using Gelatin
« on: October 06, 2015, 02:13:09 PM »
Just for the hell of it I added some yesterday to a very heavily dry hopped saison with 20% oats. It will be interesting if it can get through that haze.

Gelatin wouldn't be expected to be very effective against protein or polyphenol haze. Just a heads-up in case you don't get what you're looking for (ha!).

General Homebrew Discussion / Re: Dosing thought?
« on: October 06, 2015, 02:10:03 PM »
top off the base beer to 100 mL again

I'm wondering what that means precisely. If you're tasting from the 100 mL sample, then tracking the concentration gets trickier, but not impossible.

For example, if you make a 1% solution, then drink 45 mL, then top off to 100 mL, then add another 1 mL vodka, you'd be at about a 1.55% solution. Repeat and it's a ~1.85% solution, etc.

Beer Recipes / Re: Two Cherry Wood Smoked Malt Recipes - Thoughts please!
« on: October 06, 2015, 01:28:06 PM »
I did a cherrywood smoked porter a couple years ago. It had a more conventional porter grain bill, but with 30% cherrywood malt I liked the result.

Yeast and Fermentation / Re: New starter procedure trial
« on: October 06, 2015, 01:24:30 PM »
Is the foam continuously aerating it as it settles?  Kai has done an experiment with an aquarium pump and sterile filter pushing air through a tube that rests just above the surface (to avoid foaming), and it seems like this would be similar.

That's the hypothesis as I understand it. In which case the DO levels would be much higher than you'd get from simply keeping the headspace purged with air.

FWIW, I use an air pump in conjunction with a stir plate and have found that does give a little boost in cell counts at relatively low stirring speeds.

Alternately, for the lazy a shot of pure O2 at the begining is an option.  In fact, it might be superior for lager yeasts.  Any thoughts on that?

I'd be wary of injecting O2 after the yeast are in suspension. Pure oxygen is pretty toxic.

Of the 40 participants, only 17 (p=0.11) were able to correctly identify the unique beer in the triangle test

Can anyone comment on what a typical threshold for significance is in sensory testing? Any food scientists in the house? p<0.05 seems like a pretty tough standard to me, especially with relatively small sample sizes, and several of these Xbmts have been flirting with the p<0.1 range.

Yeast and Fermentation / Re: Repitching Yeast
« on: October 06, 2015, 10:47:59 AM »
You can get a decent estimate if you let the yeast fully compact in a mason jar (or something similar).  I'd have to go find the cells/mL estimate that's out there but it should be a better estimate than you could get with fresh slurry.
Can you clarify your statement? I'm not sure I follow the logic here.

If you really let the slurry compact out (i.e. a week stored just above freezing), it'll settle in at more like 3-4 billion/mL. You could then harvest that and get a more precise pitching rate due to a more accurate estimate of cell count. You could also resuspend it in known volumes of beer or water to get a little intuition for what slurries of varying thicknesses look like, in lieu of cell counts.

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