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.

Cheers!

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The challenges of the BIAB method

Today I'm returning to the subject of BIAB specifically as I've just finished brewing a black IPA and am very disappointed with my "numbers" (read OG).

I am committed to BIAB as the best way for me to brew, but I'm learning that there are several aspects of BIAB that present unique challenges as compared to the traditional Single Temperature Infusion method.

They are:

1) Mash Temperature Control,
2) Correct grain crush fineness, and
3) Effective wort extraction from the grain bag.


Mash Temperature Control - The BIAB method presents a challenge in maintaining consistent temperature throughout the vessel.  This is due to the fact that unlike traditional all-grain techniques that use a cooler with no heat source for a mash tun, BIAB typically uses either a propane burner, or electric brewstick as a heatsource available during the mash process. This requires that a buffer zone of water be used to prevent the bag from burning on the bottom of the vessel.  This can result in significant temperature differences between the bottom of the vessel and the mash.  Furthermore, the brew bag (typically made from voile) combined with the grains act as a barrier to the natural flow of water throughout the vessel/grains.

To address these challenges, the BAIB'er needs to do a few things.  First, in a set up such as mine (below) where a digital controller tracks the wort temperature, make sure that the thermocouple/temperature probe is in the buffer zone, or close to the bottom of the vessel.  Here is where the water will be the hottest, and this is where you want to monitor temperature so that you don't get it too hot.

 My keggle setup - note possible temperature differences possible if thermocouple is not in the buffer zone, or regular stirring is not done.

[On a side note, when I started with BIAB, I heated my water to 13 degrees over the desired temperature assuming that the grains would cool things down to the desired mashing temperature (This is the what traditional AG brewers experience when using a cooler).  My experience with this setup has been that the grain causes very little temperature drop.  I have not documented the actual drop, but I know it's a lot less than 13 degrees.]

Second, ensure frequent stirring of the mash to encourage circulation of the water throughout your grain bag, and also to even out the temperature.

Grain Crush/Fineness - My local brew shop owner likes to tease me about being a BIAB'er, and when I purchased my grain bill for this black IPA, he asked me if I wanted him to crush it (knowing that I like a finer crush than his mill is set for).  I let him go ahead, and unfortunately I did not re-crush it on brew day.

All went smoothly with my electric BIAB set up on brew day.  This was the first time I used my "upgraded" control box with a digital temperature controller, and it did fine.

Upgraded Brewstick Control Box

The OG on this fine recipe was supposed to be 1.070, but in the end I had achieved only 1.054.  I think the coarser crush contributed to my low OG.  From now on, I will re-crush at least once, as the worry of a stuck sparge is not an issue with BIAB. I may even try wet milling (spraying the grains a bit in an effort to keep the hulls from splitting apart).  I had heard of this technique, but recently saw it done on a YouTube video here.

Ideally, you want as much surface area of the crushed grain to be in contact with the water during the mash time.  Just as crushed ice cools a drink faster than larger cubes, finely crushed grains will be converted more efficiently because more surface area of the grains is available to the diastatic enzymes to act on.


 Effective Wort Extraction from the Grain Bag - One of the upsides of BIAB is that you don't have to sparge.  This is also one of the downsides, because even though most of the wort drips out of the bag,

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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!

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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 Homebrewtalk.com 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 then...so long for now.....

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