a
Partial Mash
**
Spice, Herb, or Vegetable Beer
**
by
**
Zigmister
**

1.202

OG

1.050

FG

0

IBU

9

SRM

19.8%

ABV

Recipe does not conform to the Spice, Herb, or Vegetable Beer style.

The brew kettles are actually pictured to be 60 gallon soup kettles.

Based on space considerations, you could still fit 100 lbs of grain in the 60 gal kettle, but it's just not possible to do a full volume BIAB in that case. You can't fit 60 gal of water with 100 lb of cracked grain in a 60 gal kettle because the known density of both exceeds the kettle capacity. (60 gal strike water volume = 50 gal batch size + 8% boil off (4 gal) + 6 gal absorbed in 100 lb)

With a density of 31 lb per cuft, 100 lb of grain will take up 24.13073 gal (3.22581 cuft) in the kettle with a 60 gal capacity (or 8.02086 cuft). This leaves about 35.86927 gal (4.79505 cuft) of water when filled to the brim.

That would be a water to grain ratio of 1.43477 qt per lb

(35.86927 gal * 4 qt per gal = 143.47708 qt)

(143.47708 qt / 100 lb = 1.43477 qt per lb)

In order to reach that 1.200 OG for a 20% beer using entirely all grain, consider 2 Row with 37 points per pound of grain. For 50 gallons into the fermentor, at max extraction (100% conversion) that's about 270.27 lb of grain.

(37 ppg * {G} lb / 50 gal = 200 OG) or

(200 OG / 37 ppg * 50 gal = 270.27 lb)

270.27027 lb / 31 lb per cuft = 8.71840 cuft, which is greater than the 60 gal capacity of the kettle (8.02086 cuft) even without water.

So, adding malt extract would be the next step. Considering that 100-110 lb of grain is making its way into a "partial mash", at max extraction (100% conversion) 100 lb of 2 Row would yield 68.51852 OG in 54 gal of pre-boil wort, 131.48148 points short of 120 OG.

DME Light has 42 points per pound of grain. (131.48148 OG / 42 ppg * 50 gal = 156.52557 lb of DME). I couldn't find a solid source for how dense DME is, but I found one that lists 156.52557 lb of DME = 13.95944 gal and I don't know how soluble that would really be into 50 gallons of near post-boil wort, or if it would overflow a 60 gallon capacity kettle. There may be more boil down to boil away more water to leave that 120 OG wort.

I don't believe that using a conversion efficiency of 65% is entirely accurate to BIAB. It is possible to get 80%+ efficiency consistently using the right bag materials and crush, and boil off can also influence a higher percentage on the kettle efficiency and also extending to the brewhouse efficiency.

In my conclusion, I don't think we have enough facts to say that a 20% abv beer could be made on that kind of system. We know that using 100% grain isn't a possibility because of space constraints. If doing a partial mash with the stated amount of grain, then introducing dry malt extract into the boil, it may be possible... if the density of the large amount of DME does not cause the kettle to overflow. There is enough wiggle room in the efficiency numbers to indicate that it may be possible, but at great limits to the capacity of the kettle. They very well might be brewing at the very edge of capacity.

Amount | Fermentable | Maltster | Use | PPG | Color |
---|---|---|---|---|---|

156.53 lb | Dry Malt Extract - Light | Any | Boil | 42 | 4 °L |

100.0 lb | 2-Row (US) | Any | Mash | 37 | 1 °L |

Amount | Hop | Time | Use | Form | AA |
---|

Name | Lab/Product | Attenuation |
---|---|---|

American Ale | Wyeast 1056 | 75.0% |

- Batch Size 50.0 gal
- Boil Time 60 min

- Efficiency 95.0%

- Mash Tun Volume 10.0 gal
- Kettle Volume 8.0 gal
- Mash Efficiency 75.0%

- Primary 7 days
- Secondary —

- IBU Formula Tinseth

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