Mistakes Made, Lessons Learnt And Some Q's About Gravity.

[Fat Bastard]

Did my first BIAB yesterday using this recipe which I developed myself with help from here and Brewmate:

Bongin Bongin IPA #1a (American IPA)

Original Gravity (OG): 1.068 (P): 16.6
Final Gravity (FG): 1.017 (P): 4.3
Alcohol (ABV): 6.68 %
Colour (SRM): 14.7 (EBC): 29.0
Bitterness (IBU): 62.0 (Average)

82.8% Pale Malt
8.28% Crystal 60
8.28% Vienna
0.64% Black Malt

1.5 g/L Super Alpha (12% Alpha) @ 60 Minutes (Boil)
1.2 g/L D Saaz (5.4% Alpha) @ 5 Minutes (Boil)
1.2 g/L Nelson Sauvin (11.5% Alpha) @ 5 Minutes (Boil)
1 g/L Pacific Gem (13.7% Alpha) @ 5 Minutes (Boil)
2 g/L D Saaz (5.4% Alpha) @ 7 Days (Dry Hop)

0.0 g/L Whirlfloc Tablet @ 10 Minutes (Boil)

Single step Infusion at 66C for 90 Minutes. Boil for 60 Minutes

Fermented at 19C with Safale US-05


Recipe Generated with BrewMate

Lessons learnt:

The centre of the mash is probably not the ideal place to take temperature readings from. My kettle was supposed to be temp. controlled with the probe at the same level as the element, but the damn second hand controller blew up in testing so I had to revert to the standard method of lagging the pot. Took a reading at 66 degrees, threw some blankets on and left it. Half an hour later, when I checked on it, the mash was 71 degrees. Damn. I'd stirred the buggery out of it before taking the initial reading, so my guess is that the false bottom in my kettle makes some areas impossible to stir up properly. I left the lid off and it dropped back down to 66 over the course of the next hour.

BIAB is ok if you have the headspace to lift the bag out. I didn't and had to spoon the mash out with a slotted spoon into some handy swiss voile squares (I suspected this might be the case and had prepared) What a pain in the arse.

After sparging and squeezing 4 mini bags, my fingers were burned to buggery, and I was only getting a refrac of 1.060.

Boil went smoothly, added hops at 60 minutes and 5 minutes. Forgot the whirlfloc at 15minutes, so I chucked it in at the end.

Lessons Learnt: Use a damn hop-sock. My whacky-do home made hop-blocker lived up to it's name and blocked immediately, resulting in a tiny trickle coming out the end of my plate chiller. It took nearly an hour to drain to the level I could see the top of the hose clamp holding it on, so I ripped it off (more burned fingers) and filtered the remaining wort through some more swiss voile, which also blocked rapidly. I had the shits at this point and just dumped the rest into the fermenter. This raised the temp to about 26 degrees, so it was all good, but there's an awful lot of mud in the fermenter now.

Questions About Gravity: I hit 1.060 post mash (target 1.064), so I expected not to hit my post boil target of 1.068, but I hit it anyway, which I was pleased about. I saved a bit of the wort, and after clearing the gear away, re tested it. I got 1.078 from the refractometer and cross checked it wth the hydro and got a reading of 1.080. I took a sample from the fermenter this morning and got 1.074. All samples were cooled to ambient in the bulb of the dropper sitting in a glass of ambient temperatue water.

Which reading is right? If it really is 1.080, my efficiency is about 83%, which is probably possible, but not for a first timer like me.

The wort tastes super sweet, with a hint of caramel which seems to be overpowering the hops, but it's certainly palatable, and if the ferment goes ok, should turn into drinkable beer!

Cheers for reading my long post, and thanks to all the folks who've answered my questions either directly or in threads I've read. I've been reading this site constantly for the last couple of months, and it's a real font of knowledge!

 

[RdeVjun]

Sounds like a run of the mill "my first ever BIAB" to me!
Start lagging and ditch the temp control, it is so much more of a PITA than it could possibly be worth, at least at this early stage in your all- grain career. I lose just 0.5 C even in winter- the secret is in pre- heating it, leaving the mash in peace and solitude (i.e. don't lift the lid every 10 minutes to check) and just lagging thoroughly. That way one of the most critical elements of mashing is taking care of itself.
There's no actual volumes with that report from BrewMate, what is the volume in the fermenter and what was the target? I suspect you got less than you anticipated, however efficiency in mid- 80s is not unheard of with sparged BIAB. You may well be able to dilute this to the target, I do just that all the time with MaxiBIAB.
Don't worry about the wort sweetness, the yeast will take care of that for you, then at the end you could well have nicely balanced beer. :icon_cheers:

 

[Fat Bastard]

Should have specified that I hit all the targets for volumes. Was aiming to get a 19 litre batch and ended up with 20l in the kettle post boil, as measured with my patent knife marks on the back of a long spoon measuring stick.

Still confused as to why the refrac taken directly from the kettle post boil was so much lower than the readings taken from the fermenter and the stuff left over.

If the reading was 1.080 when I transferred to the fermenter, I would have diluted it a bit. According to brewmate, this will be a near 8% IPA, when I was aiming for 6.66%

 

[RdeVjun]

Spatial variability perhaps? :lol:
With your refractometer, there could've been some water left stuck to either the prism or cover surfaces after the previous use and clean, that would explain a low measurement. Its not likely to be the reason, but do take a moment to check all your fundamental measurement devices, so verify that mass, volume and temperature are all correct. The main thing is you've got what will be some beer happening and learnt a bit about which processes suit you and those which just don't. :icon_cheers:

 

[Shortz]

Silly thought about the gravity, post mash, did you adjust for the temperature? Wouldn't it be hotter therefore higher SG?

 

[stux]

If your refractometer has an SG scale, the scale is not accurate at high gravities

Best to use brix and then a less naive conversion than "multiply by 4"

83% is my normal mash efficiency with no sparge biab

And I've had up to 97%

 

[Fat Bastard]

Silly thought about the gravity, post mash, did you adjust for the temperature? Wouldn't it be hotter therefore higher SG?

All samples were cooled to ambient before testing.

If your refractometer has an SG scale, the scale is not accurate at high gravities

Best to use brix and then a less naive conversion than "multiply by 4"

83% is my normal mash efficiency with no sparge biab

And I've had up to 97%

That sounds entirely plausible. I was reading off the SG scale on the refractometer. When I tested the sample after I'd packed everything away, I was getting 1.078 off the refrac and 1.080 off the hydro.

On my scale 1.078 = 20 Brix, according to the calculator in the tab up there^^^, 20 Brix is equivalant to 1.084 SG.

I've either completely miss-read it, or the cheapo refractometer is a dud!