Messages

781

Yeast and Fermentation / Re: Wort aeration needed?

« on: December 29, 2010, 08:47:00 AM »

I am in the camp that aerates.  Even though you've created a population of healthy yeast with high sterols, they can still use more sterols as they acclimate and multiply in the lag and growth phases.  This is especially important with higher gravity worts. 

The good thing is that you indicate that you've made a large starter.  Have you compared that estimated yeast population to one of those pitching guides such as Mr. Malty?  If you're overpitching, then the need for aeration is reduced.  If you're only marginal, then aeration is still warranted. 

Remember that the effects of aeration only last about 30 minutes according to the new book on yeast.  The yeast consume oxygen very quickly according to that book.

782

General Homebrew Discussion / Re: pH check

« on: December 28, 2010, 02:52:50 PM »

The highest recommended room-temp mash temp is about 5.8 (from Malting and Brewing Science), so the true room-temp pH range for mashing is 5.4 to 5.8.  Lower mash pH improves the fermentability of the wort.  So if your goal is fermentability, then the low end of the range is desirable.  If you're not looking for fermentability, then the upper end is preferred.

783

Extract/Partial Mash Brewing / Re: specialty grain liquid: adding earlier versus later?

« on: December 27, 2010, 08:11:01 AM »

It is preferrable to add the liquid at the early part of the boil.  There are proteins and other compounds that need to be boiled so that they will coagulate and drop.  In addition, that liquid has some extract and the gravity of the remaining boil would be a little low and the hop extraction would be increased somewhat.  That could be compensated for by reducing the hopping very slightly. 

I don't think that the small volume of liquid is really going to do much in your quest to chill the wort after the boil.  Its maybe 10 to 20 percent of the batch volume and even if it was at 32F, its heat sink capacity wouldn't come close to the heat content of the remainder of the batch at around 200F.

784

General Homebrew Discussion / Re: Refractometer - Which one is best?

« on: December 26, 2010, 08:36:12 AM »

Optics are way out of my field.  I have no idea why the interface sharpens with time.  I'll have to test what Kai is saying, maybe it does sharpen faster upside down?

785

General Homebrew Discussion / Re: Refractometer - Which one is best?

« on: December 25, 2010, 06:17:19 PM »

I also have one of the inexpensive Ebay sourced units.  I have to disagree with letting the unit and sample cool off for only 20 seconds.  I find that it actually takes about 1 to 2 minutes for the reading to stabilize even though the unit says it has ATC. 

I don't have a problem waiting, but I just want to caution folks about registering the reading too early.  Give it a little more time.  I also find that the interface line between the white and blue zone sharpens with more time.  It starts out very fuzzy and sharpens in a few minutes.

786

All Grain Brewing / Re: All Maris-Otter IPA input needed

« on: December 24, 2010, 01:24:06 PM »

Something is very wrong with the water profile posted.  It doesn't come close to balancing.  The alkalinity number indicates that the HCO3 content is 28 ppm, but the anion total is still too low. 

But, with the information posted so far, its a really soft and low alkalinity water.  It may need slight increase in alkalinity but it really shouldn't be necessary.  If you're adding gypsum to this water to bump the sulfate content, then you are driving the residual alkalinity far too low and then adding alkalinity is imperative.  You'll need to report back with what is mis-typed on the water report and what sort of other mineral additions you've done in the past. 

787

All Grain Brewing / Re: Water Analysis

« on: December 23, 2010, 02:17:10 PM »

Surface water source water quality can vary significantly since they represent a combination of groundwater (that seeps into the lake or stream) and rainwater that runs off the land.  The mineralization of these waters can vary with each rainfall event (or lack of rainfall). 

If you're dealing with a source that can vary, I would recommend getting an aquarium test kit that includes hardness and alkalinity analyses.  I think Kai has some information on this at his website.  The are cheap ($10 to $12 I think).  Don't get test strips, get a kit or kits that have colormetric chemicals that you add to the sample and compare to a color strip.  I think they are more accurate and easy to read.

Once you have benchmarked your water quality with lab testing and have performed a corresponding aquarium test, you can then have an idea of how to adjust your water to overcome the variability. 

788

Yeast and Fermentation / Re: WY1007 vs. WY2565

« on: December 23, 2010, 10:15:20 AM »

I'm with Denny on this one.  The 2565 makes a much better Kolsch than the 1007.  I picked up the proper Winey overtones after it had finished.  This yeast suprised me since it was the first yeast that I had used that throws a sulfur aroma during ferment.  It went away completely though. 

I tried 1007 on many brews over the years and also had beers from incredible breweries (Rocky River Brewing in OH) and finally came to the conclusion that there is just something in that yeast's ferment that I don't prefer.  YMMV.

789

All Grain Brewing / Re: Water Analysis

« on: December 23, 2010, 10:08:55 AM »

Tom is correct, almost any water-tight container will do.  The thing I want to add is that you only need to send a small amount of water.  I recently sent my samples in to Ward using old White lab yeast vials.  It was enough water.  You don't won't to pay a bunch to ship water, do you?

790

All Grain Brewing / Re: All Maris-Otter IPA input needed

« on: December 23, 2010, 10:06:01 AM »

I experimented with APAs and AIPAs several years ago, investigating the appropriate grist composition when you have high hop flavor and aroma.  My goal was to increase the complexity of malt flavors, but not really move the wort color from the style guideline ranges. 

I produced great tasting beers with nice malt complexity underlying the bittering, flavor and aroma of the American hops.  But, the complexity of the malt flavor actually interferred with the hop flavor and aroma and clashed.  While they were within style, it was apparent to me that when dealing with the level of hopping in a good APA or AIPA, the malt flavor needed to be cleaner and nearer to a single-dimensional malt flavor. 

I now have been more typically using a grist composed of mostly pale 2-row with a single crystal malt.  I see that there has been a popularization of Tasty's APA and it uses pale and pils with some crystal.  Seems to be in line with my thoughts, but even lighter malt flavor.    I don't see why using either a single pale malt or a simple combination of base malts couldn't produce a good version of these styles as long as the brewer keeps the crystal addition fairly simple.

791

Homebrew Clubs / Re: Technical brewing education in brewing clubs

« on: December 22, 2010, 12:03:58 PM »

In my first club, North Florida Brewers League, there were separate meetings for the technical sessions. 

The regular club meetings were held at a restaurant bar that allowed us to meet, eat, and drink and also bring our homebrew for informal evaluation (I wouldn't really call it judging).  These regular meetings were specifically geared to be social with a minor education provided on a monthly beer style and then we had the tasting and evaluation.  No heavy technical stuff was typically included in those meetings.   These were typically fairly large meetings.

The technical meetings were typically with smaller groups and they were held at a member's house.  These did get into some nifty technical and stylistic evaluations and discussions.   The thought was that these technical discussions turned off some people and were sometimes outside the interests of general club members.  Having the technical sessions separate let the folks who were really interested in the subject get together and focus on a more closely instead of slipping this into a meeting where some might either be dozing off or disturbing the geeks.

 

792

Ingredients / Re: Palmer Spreadsheet Error

« on: December 19, 2010, 03:52:43 PM »

The mash is buffered, but the hydroxide is not.  It will consume any proton available.  This is unlike the alkaline buffer, bicarbonate which doesn't have the power to consume the weaker acids.  Therefore, the pH will rise until all the hydroxide is consumed. 

I don't think it will really make a difference to a brewer who is careful and precise with their mineral and acid additions.  But it could make a difference to the brewer that adds stuff based on the TLAR theory (that looks about right). 

793

Ingredients / Re: Palmer Spreadsheet Error

« on: December 19, 2010, 10:41:37 AM »

Slaked lime (aka Pickling Lime) is sometimes used to add alkalinity in drinking water.  In that case, air or CO2 are bubbled through the slaked lime solution to react the excess OH ions back down to HCO3 ions.  As some of you may know, my profession is in water engineering.

But given the fact that our primary concern in mashing dark grains is avoiding an excessive pH drop, we don't necessarily need to convert the acid consuming OH ions into less reactive (but still acid consuming) HCO3 ions.  The only thing with working with the slaked lime is that it will be far less forgiving.  This is just like working with an acid.  You would need to know what you're doing and add exact amounts.  

I'll work through the dosing quantification for slaked lime and get back to folks on this. OH and HCO3 are roughly interchangable as alkalinity producers, its just that OH is not a buffer and will automatically consume acid without moderation.  So there is no leeway.

Lime will get us away from the problem of limited chalk solubility.

794

All Grain Brewing / Re: Step Mash Profiles and Fermentibility

« on: December 18, 2010, 06:20:52 AM »

Kai,

There was one point in your post that raised a question:

- more highly kilned malts will lower fermentability but that doesn’t go linear with color.
 
What about looking at the effect of highly kilned malts with respect to percent of grist?  Maybe there is a correlation there?

795

All Grain Brewing / Re: Mash Out?

« on: December 17, 2010, 11:08:29 AM »

Um guys, it doesn't matter if there was a million feet of water column over the grain bed as long as there is no flow through the bed.  The net downward force on the grain bed is the same as if there was 1 inch of water of the grain bed.  Its when there is flow that the stress on the grain bed can go up some.

In this case, there is a concept called Effective Stress that applies here.  This is a primary concept to geotechnical engineering, which is what my first Masters degree is in.

As was alluded to by the comments, we know that the pressure applied by the water increases as we go deeper under the water surface.  But that water pressure doesn't just act on the top of the grain bed, it acts on each grain within the grain bed too.  So to simplify, consider a single grain that is small so that the water pressure at the top of the grain is roughly the same as at the bottom of the grain. 

Since water pressure always acts perpendicular to the surface to which it is applied and since there is equal upward facing surface area as downward facing surface area, the net effect is that the water force acting downward on a particle is the same as the water force acting upward on that particle when there is no flow. 

The force imposed by flow is another matter and the depth of the water column over the bed can have an effect.  As I mention above, the pressure on the top of the bed is roughly the same as on the bottom of the bed when there is no flow.  To cause flow, you have to have a pressure gradient across the bed.  For our tuns, we open a valve that is connected to the outside world where the water pressure is essentially zero.  If we open the valve a crack, we can keep the pressure at the bottom of the bed only a little lower than the pressure at the top.  But, if we open the valve all the way, we could get close to zero water pressure at the bottom of the bed.  This is where the depth of the water column over the bed plays a part. 

If I've got a million feet of water head over the grain bed and I make a mistake and open the valve too much, then I could be placing a 1,000,000' - 0' = 1,000,000 feet of head on the grain bed.  But if I only have a foot of water over the grain bed, then the worst I could do is apply 1' - 0' = 1 foot of head on the grain bed.   

So, its not really that putting a lot of water over your grain bed is bad.  Its that you could place a lot of stress on the grain bed if you open the outlet valve too much and draw off wort too fast.

So its not the water's fault, its the operator's fault. 

And regarding the issue with Batch spargers, they are draining all the wort from the bed.  Recall that I mentioned that the water pressure acts on all surfaces.  As we drain the bed, then a portion of the bed is above the liquid surface and instead being partially supported by the water pressure, that grain is applying all its soggy weight to the rest of the bed.  That can certainly compress the bed and is a good reason why you should not perform batch sparging.  Don't drain the bed until the final runoff.