Thursday, May 31, 2012

Maximizing wort extraction from BIAB

One of my frustrations with the BIAB method is that once mashing is complete, I feel that too much of the wort remains in the bag.  And even though a "stuck sparge" is supposed to be impossible with BIAB, there sure does seem to be too much sweet wort trapped in the grain bag that is unaffected by gravity while it hangs above my keggle.

I've tried spinning the bag to squeeze wort out, and I've put the grain bag in a collander on my keggle and tried to push on it and squeeze as much out as possible without burning my hands.  With either of these methods I can usually hit my numbers, but I'd like to figure out a way to avoid all the squeezing, pressing, etc.

I referred back to John Plamer's How to Brew book to try and get a scientific explanation of the sparging/lautering.  Appendix F of the book discusses the fluid dynamics of water through a traditional cooler mash tun grain bed.  In this case, the grain bed is only being affected by the downward force of gravity.  There is no lateral force on the sides of the grain bed, so the flow resistance is determined solely by the weight of the sparge water flowing through it, and the weight of the grain bed itself.

For BIAB method however, the grain bed/bag is also subjected to the lateral pressures of the grain bag itself, which push the grain particle closer together, increasing the flow resistance for the wort.

To prevent this, I plan to use a cake rack (or similar) to prevent the bag from collapsing around the grain bed as the bag is pulled from the vessel.  I have not determined if placing the rack inside the bag or under the bag is best.

I'm hoping to try this in the next week when I brew up a Gumballhead clone.  I'll report back my findings.

In the meantime, please let me know your thoughts on this and any other ideas you have to allow wort to flow more freely from the bag.


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Wednesday, May 2, 2012

General tips for the beginning brewer

I'm going to deviate from my BIAB slant today to share a few important general tips that will move you into the major leagues of brewing quickly, and keep your beer from having that "homebrew" taste.

Several of my early batches were "good", but still had that slight off-flavor that is not objectionable, but you notice.  All of your friends and family will tell you it's good beer, but you can still see that look on their face after they take the first sip that tells you they're only being half-truthful.  They can tell it's homebrew.

Here are a few things that, if you pay attention to will make your beer much better.

1.  Fermenting temperature - Many beginning homebrewers think that sitting their carboy or plastic bucket in the corner of the living room or a closet with a towel over it is good enough.  WRONG!  I did this initially, but finally realized that it was too warm there.  My wife and daughter really like the house warm in the winter, and I'm forced to crank the heat up to 75 Deg F.  While the yeast will survive at 75 deg with no problem, at this temperature the yeast are in overdrive, and produce a several by-products that will affect the taste of your beer.  If you want learn the nitty-gritty about what the yeast produce, check out the Yeast book on my Recommended Books page.

Even if you keep your thermostat at a lower temperature, you'd be surprised at how much variation there can be. I significantly improved my beers by setting up a water bath system as shown below.

What you're looking at is (aside from a 6 gallon carboy full of Blue Moon wheat clone) a plastic storage bin filled with water, with a 300W aquarium heater (similar to a Fluval E 300-Watt Electronic Heater ) and submersible pump (like this one: Active Aqua Submersible Water Pump 160 GPH ).  The heater is on the left with the green end cap.  The pump can't be seen but is attached to the rear wall of the bin.  Also floating around in there is a thermometer that I monitor temperature with.  The black straps you see are my Brew Hauler (The Brew Hauler - Carboy Carrier ).  I have this sitting in my shop which stays at around 55-65 degrees F.

There are other heaters available, but make sure that the one you pick is adjustable down to 68 degrees F or lower.  I chose a 300 W heater based on a formula in Chapter 4 of the Yeast book mentioned above.  The beauty of this set up is that the heater will keep the water at the proper temperature and the pump keeps the water circulating so that the temperature is even throughout.

Temperature variations in your fermenter will affect the yeast in a bad way.  You want to keep a constant temperature, and I have had good success with this arrangement.

2.  Yeast Starters - One of the big things I learned by reading the Yeast book is the importance of pitching the correct amount of yeast.  You need to have enough yeast introduced into your wort so that it moves from the Lag phase to the Exponential Growth phase within 15 hours.  In most cases, this means that you'll need to make a starter, as the number of yeast cells contained in your dry yeast packet, or liquid yeast vial is not going to be enough.  In general, the rule for calculating yeast cell counts is

(1 million) X (milliliters of wort) X (degrees Plato of the wort)

(I've taken this formula from the Yeast book mentioned above)

In some cases, the yeast cell count in the packet or vial you purchase can be less than half of the optimal cell count needed to get your wort fermenting properly in the desired timeframe.

Making a yeast starter is the solution, as it is simple and prevents the yeast from making high levels of diacetyl and acetaldehyde which contribute off-flavors to your beer.

I will not get into the process of making a yeast starter here, as there are numerous well-done explanations of the process including this one by John Palmer from his book How to Brew: Everything You Need To Know To Brew Beer Right The First Time.

While these tips are not specific to Brewing in a Bag, I wanted to share my thoughts here, as it took me longer than it should have to figure these things out.  I hope these help you get to the major leagues of homebrewing quickly!

Until next time....Cheers!

Tuesday, May 1, 2012

Electric heating system

In this post, I'll lay out the details of the electric (heatstick) based system that I have been using.  As I mentioned in my previous post, an electric system was what I settled on after considering a propane system.

There seems to be some trepidation in the brewing community regarding systems that involve water and electricity, and with good reason.  If you don't have your system properly designed and installed it could mean a nasty shock at the least, and death at worst.  Without a good understanding of electricity, putting together an electric heating system is a daunting task, and is probably one reason why propane is more popular, at least for now.

Since my background is in electrical engineering, I was somewhat less intimidated with this approach, although I have to admit that I still had to do a lot of reading to convince myself that I wanted to embark on this path.  I had seen several sites that described a heatstick constructed of a water heater element attached to several standard 1-1/2" drain pipe components.  Most used 120VAC elements which was convenient for plugging into a standard outlet.  I was more interested in a higher wattage element that would be capable of quickly bringing 5-10 gallons of water up to mash temperature (~150 Degrees F) in a reasonable time (10-15minutes).  These higher wattage elements required 220VAC, similar to what your electric clothes dryer needs, meaning that I'd need to have a 220VAC outlet installed where I wanted to brew (my basement shop and my garage).  Also, I wanted a way to vary the heatstick output so I needed a way to either vary the voltage or the duty-cycle.  I chose the latter after reading a thread on that detailed how a Pulse-Wave Modulator circuit board from Bakatronics could be used to turn on and off a solid-state relay (you'll want this heatsink too) to control the heatstick.  The picture below shows a box from HomeDepot that I used to mount the circuit board and the solid stat relay.

Without going into all the details, I ended up with the system shown below, which (with one exception) has serverd me well in the last 6 months of brewing.
You'll notice that I decided to bend the water heater element 90degress so that it lays on the bottom of my keggle.  I emailed Camco before I did this and got this response:
The element sheath is made from Incoloy 840 and the interior is filled with a highly compacted ceramic powder. Bending an element creates gaps in the ceramic that cause high temperature spots. A tighter bend radius gives larger gaps. The larger the gaps are, the higher the temperature will be. High temperatures will reduce the life of the element. If the bend is too tight the element will crack. Too address the difficulties, we use specialized bending equipment and compression dies that we have developed just for these elements.
I don’t recommend bending the element, but if you can't find a way around it, use the largest bend radius possible.

The heatstick is placed into my keggle as shown below
In order to keep the grain bag from being burned by the heatstick, I settled on a 10" stainless steel vegetable steamer to act as a false bottom in the keg as shown below

As you can see from the photo below, I used some stainless steel bolts to serve as feet that hold the steamer several inches off the bottom of the keggle

I've recently purchased a digital temperature controller that I plan on using to control the heatstick in lieu of the PWM circuit board I now use.  More details on that to follow.

In my next post, I'll discuss a few important tips for beginning homebrewers that I learned about the hard way including temperature control of the fermenter, and proper yeast pitching.

Until long for now.....