First BIAB

[rhit87]

I have been extract brewing for several years and recently bought a used Barley Crusher and refractometer, so decided to give BIAB a try. I did a Northern Brewer 3 gallon Chocolate Milk Stout https://www.northernbrewer.com/documentation/allgrain/BIAB-AG-ChocolateMilkStout.pdf. I don't have a feeler guage, so am not sure what the crusher gap was. The guy I bought it from said it was set at 0.038 and I just eye balled it to about half of that.

I started out with 4.5 gallons of half tap and half RO water. Recipe calls for 152 mash temp and, according to calculator I used, strike water should have been 158, but I overshot that and started at 162. After adding my grain bag and giving a good stir, I was at 158, so added some cold water and got down to 154. I wrapped my kettle in two old sleeping bags and started my 75 minute timer. At 25 minutes, I gave it a stir and temp was 152. At 50 minutes, another stir and temp was 149.7. At 75 minutes, temp was 147.7. Per the recipe, I raised the temp to 170 and mashed out for 10 minutes.

At this point, I learned my first lesson. I raised the bag too fast and ended up spilling over the side of my kettle. Next time I will raise it to just above the liquid level and let it drain a bit before raising all the way above kettle.

I squeezed the bag well and had a pre-boil volume of 4.25 gallons. My refractometer showed pre-boil SG of 1.050.

All other aspects of the boil, chilling and transferring 3.25 gallons to fermenter, and aeration went as expected.

Here is my second lesson. I checked OG with the refractometer and got 1.067. Recipe indicates OG of 1.052, so I thought this can't be right. I checked refractometer with RO water and got 1.005, so figured that my OG really is 1.062 which is still high. I then checked with my hydrometer and read 1.058. Checking with RO water gave a reading of 0.998, so I'm guessing my OG is actually 1.060. Am I right about that?

Is it possible for my OG to be that high? I feel that the wort was well mixed when I drew my samples, but don't have any other explanation.

 

[RM-MN]

I have been extract brewing for several years and recently bought a used Barley Crusher and refractometer, so decided to give BIAB a try. I did a Northern Brewer 3 gallon Chocolate Milk Stout https://www.northernbrewer.com/documentation/allgrain/BIAB-AG-ChocolateMilkStout.pdf. I don't have a feeler guage, so am not sure what the crusher gap was. The guy I bought it from said it was set at 0.038 and I just eye balled it to about half of that.

I started out with 4.5 gallons of half tap and half RO water. Recipe calls for 152 mash temp and, according to calculator I used, strike water should have been 158, but I overshot that and started at 162. After adding my grain bag and giving a good stir, I was at 158, so added some cold water and got down to 154. I wrapped my kettle in two old sleeping bags and started my 75 minute timer. At 25 minutes, I gave it a stir and temp was 152. At 50 minutes, another stir and temp was 149.7. At 75 minutes, temp was 147.7. Per the recipe, I raised the temp to 170 and mashed out for 10 minutes.

At this point, I learned my first lesson. I raised the bag too fast and ended up spilling over the side of my kettle. Next time I will raise it to just above the liquid level and let it drain a bit before raising all the way above kettle.

I squeezed the bag well and had a pre-boil volume of 4.25 gallons. My refractometer showed pre-boil SG of 1.050.

All other aspects of the boil, chilling and transferring 3.25 gallons to fermenter, and aeration went as expected.

Here is my second lesson. I checked OG with the refractometer and got 1.067. Recipe indicates OG of 1.052, so I thought this can't be right. I checked refractometer with RO water and got 1.005, so figured that my OG really is 1.062 which is still high. I then checked with my hydrometer and read 1.058. Checking with RO water gave a reading of 0.998, so I'm guessing my OG is actually 1.060. Am I right about that?

Is it possible for my OG to be that high? I feel that the wort was well mixed when I drew my samples, but don't have any other explanation.

It sure could be. Many recipes are written with an expectation of about 70% brewhouse efficiency. It's pretty easy to exceed that with BIAB if your crush is good. I haven't had efficiency lower than 80% since I started BIAB.

With your Barley Crusher set tight like you have it the mash probably converted in the first 20 minutes so the falling temperature during your 75 minute mash is of no consequence. A majority of the conversion may have occurred while you were bringing the temerature from 158 to 154. It all depends on how quickly the starch was gelatinized. You may have gotten the same results from only mashing for 30 minutes but the longer mash doesn't hurt anything and if conversion wasn't complete in 30 minutes it surely was by 75. If conversion was complete, the mash out accomplished nothing except to start heating the wort toward the boil. Mash out is only really applicable to fly sparging and then only useful if conversion is not complete and you want to stop it.

Your refractometer is probably temperature compensated so you can take a reading quickly. Hydrometers only are accurate at the temperature they are calibrated for, often 60 degrees F.

 

[doug293cz]

One thing to worry about with a refractometer is evaporation of water from hot samples. Because of the extremely small sample size, any evaporation of water from the sample can raise the SG of the sample significantly. For that reason, I take a sample of a couple of oz, and let it cool in a covered container. The use an eyedropper to put a couple drops on the prism plate, and take the reading as fast as possible. You should also calibrate your refract to read 0 with distilled or RO water. There is usually a small screw adjustment on top just behind the prism cover.

It's also a good idea to check your refract readings against a hydrometer for several brews to see how well the two correlate, so that you can figure out a "fudge factor" for your refract if needed.

1.060 is probably a good enough estimate of your OG. Don't obsess about it too much at this early stage of your brewing. You want to work on improving all your measurement techniques to get maximum accuracy, but taking a few sessions to get there is not a big deal. And remember, when it comes to dialing in your brewing process, accurate volume measurements are just as important as accurate SG measurements.

Other than that your first brew appears to have gone quite well. As you get practice, brew days will go even smoother.

Brew on

 

[OldDirty]

Welcome to bagging! A couple of things I noticed with my initial BIAB efforts is I always overshot my pre-boil and original gravities. I've since adjusted my recipes in light of the efficiency I'm getting with my equipment. It'll take you a few brewing session to nail it down. Not much to worry about really.

As far as setting a gap for your mill, eye-balling never works. Granted, with BIAB we're not concerned about stuck sparges, I just don't like potentially milling flour. An easy way to set up your mill is with your debit or credit card. Typical credit cards have a .030 width. Gently place the card between the rollers and set your gap. Thinner cards give you a thinner gap. You want the gap uniform on the left, right and center of the rollers.

Something else I've learned. Before I pull my bag, I start twisting the bag from the opening. It helps squeezing without the hot wort on the hands issue. I slowly raise, then twist, raise then twist, etc until I'm ready to pull it out completely. Most of the run off ends up in the kettle and not on my hands.

Best of luck!

 

[rhit87]

Thank you all for the comments and suggestions. I will plan to eliminate the mash out next time to save time and start tracking my refractometer/hydrometer readings.