Author Topic: BIAB question asked out of complete ignorance.  (Read 3843 times)

Offline Zmonster

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BIAB question asked out of complete ignorance.
« on: June 10, 2018, 03:13:45 AM »
I'm about to try my first BIAB, and I have a silly question asked out of complete ignorance.

My lifestyle is (for lack of a better word) a bit "nomadic".  Unfortunately, this means I left in storage my mash tun (i.e. cooler with drainage system).  I don't really want to buy another for two reasons:  I'm saving to buy a nice stainless mash tun, and I don't want to have the cost of a redundant cooler eat into my stainless budget.  The lack of my dedicated tun is why I want to try BIAB.

What I do have, on the other hand, is my really nice cooler (i.e. ORCA).  The good news is that it will hold heat for a very long time.  The bad news is the drain on this cooler is such that it's impossible (yes, I've tried) to fit a drain system that will both allow filtering and limit "splashing" and picking up oxygen when I drain the cooler.

A minor secondary concern is the largest kettle I can find is 5 gallons, and I'm making a 3 gallon batch.  BeerSmith says I need 4.8 gallons of water to do this, but water plus grain strikes me as awful close to 5 gallons, especially if I need to add mash water to heat or cool the mash.  The cooler is 6.5 gallons, so I have a bit more flexibility there.

All the BIAB information I have show using the bag in the brew kettle, but I worry that I will not be able to hold the mash temp in the kettle.  So I was thinking it might be worth it to use the cooler, pull the bag, and then use my racking cane to transfer the wort into the brew kettle.  Yes, that's an extra step which kind of obviates the simplicity of BIAB, but it's a one time thing.  By the time I finish drinking this batch, I hope to have a stainless tun.  Does this sound feasible, or am I far too concerned with keeping the mash temp?

I'm very new to this, so I really appreciate any advice.

Offline Oginme

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Re: BIAB question asked out of complete ignorance.
« Reply #1 on: June 10, 2018, 06:44:41 AM »
As someone who does primarily full volume BIAB, I can understand where you are coming from.  You have several options for how you want to tackle your capacity constraints with a 5-gal kettle.

The first and easiest is to do full volume when the mash plus grains does not exceed the volume of the kettle.  BeerSmith will let you know if the volume is too great for your equipment by performing a capacity check on the mash tab and changing the blue dot next to the 'mash volume needed' to a red dot.  If you are near capacity, then you want to pay attention to this indicator. 

For those recipes which exceed the volume or if you just don't want to have to play around with having to worry about capacity restraints, there are also options.  The first is if you have a second or smaller pot you can do one of two things: a) you can heat up the sparge water (or not) in the second pot and then when you pull the bag of grains, plunk it down into the pot for a 'dunk sparge'.  I do this with a 3-gal pot for higher gravity beers when I do my typical 10 liter batches.  I recommend opening up the bag and giving the grains a vigorous stir in the sparge pot to get good mixing of the sugar heavy wort and the sparge water.  You can then pull the bag and combine the waters in your boil kettle.

If you do not have a second pot you can even use a fermenting bucket and cool water to do a dunk sparge. 

Another alternative is to remove the bag and then use a colander on top of the kettle to hold your bag of grains.  You can then do a 'sprinkle sparge' by slowly pouring the sparge water volume through the bag to drain back into the mash kettle.  Personally, I have found this method to be less consistent in results, but many people do this and get it to work for them.

Also, your cooler will work fine and many people do use a bag lined cooler as their mash tun.  This also helps in maintaining the temperature for the mash.

Yet another alternative is to go slightly less in your batch size: I have a 22 qt pot (20.8 liters) so I do 10 liter batches in it which gives me enough head room for all but the very highest of gravity recipes.  It also gives me enough head room in my 3-gal carboys so that I usually do not need a blow off tube for most yeasts/recipes.

Also consider your boil off rate. If your boil off rate is pretty high (>15%) then reducing your boil time to reduce your water demand can also help to make batches fit into your pot better.

Just a note on BIAB, if you choose to do a sparge step, then you will need to treat your mash profile as a standard mash and not a 'BIAB' mash as defined in the software.  This means that you will most likely need to adjust your standard grain absorption rate to what you typically get for your BIAB mashes. 

For holding the temperature of your mash kettle when doing BIAB, there are several methods that people use.  The first is to take some old blankets, sleeping bags, or insulation such as reflectix, and wrap the mash tun in those insulating layers for the duration of the mash.  The second is to use your oven to help hold temperature.  Most ovens have a lower setting of around 170F for keeping food warm.  Assuming you can fit your kettle in the oven, you can preheat (very important) your oven to 170F and then place the kettle into the oven.  Wait until your oven comes back to temperature and clicks the heating elements off (in my case it is gas, so the flames turn off) before turning the oven off.  The insulation of the oven and the surrounding air temperature inside the oven of 170F will generally keep the mash kettle within a couple of degrees F of your initial temperature.  I find this method consistent for each mash temperature I use. 

I typically don't sweat a few degrees change over the course of an hour.  Since the majority of the starch conversion happens in the first 15 to 20 minutes when the temperature is at or pretty close to my target mash temperature, I am obtaining what I want from my process. 
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