First stuck mash on Grainfather: what did I do wrong?

[GillesF]

Hi all

Today I tried brewing my first RIS on the Grainfather, unfortunately I was unable to complete brew day because of a stuck mash. Homebrewing life lesson learned I guess

I'm pretty sure that if I had used rice hulls, I wouldn't have had any problems, but could someone have a look at my recipe and check if perhaps I did something else wrong?
One thing I noticed during recipe creation is the ratio between mash water and sparge water, the latter being very low.

Here's the recipe:


Black Phillip | Imperial Bourbon Stout
Imperial Stout
11.2% / 25.9 °P
Recipe by
Gilles
All Grain

Grainfather
63.8% efficiency
Batch Volume: 12 L (3 gallon)
Boil Time: 60 min
Mash Water: 22.4 L (5.91 gallon)
Sparge Water: 0.74 L (0.19 gallon)
Total Water: 23.14 L (6.1 gallon)
Boil Volume: 18.27 L (4.82 gallon)
Pre-Boil Gravity: 1.086

Vitals
Original Gravity: 1.110
Final Gravity: 1.025
IBU (Tinseth): 68
BU/GU: 0.62
Color: 125 EBC

Mash
Temperature — 65 °C (149° F) — 60 min
Mash Out — 75 °C (167° F) — 10 min

Malts (6.999 kg)
4.9 kg (10.8 lbs) (70%) — Castle Malting Chateau Maris Otter — Grain — 4 EBC
700 g (1.5 lbs) (10%) — The Swaen GoldSwaen Brown — Grain — 220 EBC
700 g (1.5 lbs) (10%) — The Swaen PlatinumSwaen Brown Porter — Grain — 400 EBC
350 g (0.77 lbs) (5%) — The Swaen BlackSwaen Chocolate B — Grain — 900 EBC
349 g (0.77 lbs) (5%) — The Swaen PlatinumSwaen Oat Flakes — Grain — 0 EBC

Hops (140 g) --> (used Saaz & Willamette because I had these as left-overs)
35 g (1.23 oz) (19 IBU) — Saaz 4.1% — Boil — 60 min
25 g (0.88 oz) (18 IBU) — Willamette 5.3% — Boil — 60 min
20 g (0.70 oz) (11 IBU) — Willamette 5.3% — Boil — 30 min
30 g (1.05 oz) (10 IBU) — Saaz 4.1% — Boil — 20 min
30 g (1.05 oz) (11 IBU) — Willamette 5.3% — Boil — 15 min

Miscs --> RO water with minerals
6 g (0.21 oz) — Baking Soda (NaHCO3) — Mash
4.13 g (0.15 oz) — Calcium Chloride (CaCl2) — Mash
5.17 g (0.18 oz) — Epsom Salt (MgSO4) — Mash
1.03 g (0.04 oz) — Gypsum (CaSO4) — Mash
1 g (0.04 oz) — Yeast Nutrients (WLN1000) — Boil — 15 min
2 g (0.07 oz) — Irish Moss — Boil — 10 min
15 g (0.52 oz) — Bourbon Oak Chips — Secondary

Yeast
0.6 pkg — Lallemand (LalBrew) Voss Kveik 77%

Fermentation
Primary — 33 °C — 7 days
Secondary — 30 °C — 5 days
Carbonation: 2.3 CO2-vol

Water Profile
Ca2+ 60
Mg2+ 22
Na+ 79
Cl- 90
SO4-113
HCO3- 200

Thanks all!

 

[GillesF]

Also, comments about improving the recipe are welcome

The goal was to create a stout with plenty of caramel and chocolate flavours and some hints of bourbon. Little to no smoke/roast flavour and light to moderate mouthfeel.

 

[Sammy86]

Hi all

Today I tried brewing my first RIS on the Grainfather, unfortunately I was unable to complete brew day because of a stuck mash. Homebrewing life lesson learned I guess

I'm pretty sure that if I had used rice hulls, I wouldn't have had any problems, but could someone have a look at my recipe and check if perhaps I did something else wrong?
One thing I noticed during recipe creation is the ratio between mash water and sparge water, the latter being very low.

Here's the recipe:


Black Phillip | Imperial Bourbon Stout
Imperial Stout
11.2% / 25.9 °P
Recipe by
Gilles
All Grain

Grainfather
63.8% efficiency
Batch Volume: 12 L (3 gallon)
Boil Time: 60 min
Mash Water: 22.4 L (5.91 gallon)
Sparge Water: 0.74 L (0.19 gallon)
Total Water: 23.14 L (6.1 gallon)
Boil Volume: 18.27 L (4.82 gallon)
Pre-Boil Gravity: 1.086

Vitals
Original Gravity: 1.110
Final Gravity: 1.025
IBU (Tinseth): 68
BU/GU: 0.62
Color: 125 EBC

Mash
Temperature — 65 °C (149° F) — 60 min
Mash Out — 75 °C (167° F) — 10 min

Malts (6.999 kg)
4.9 kg (10.8 lbs) (70%) — Castle Malting Chateau Maris Otter — Grain — 4 EBC
700 g (1.5 lbs) (10%) — The Swaen GoldSwaen Brown — Grain — 220 EBC
700 g (1.5 lbs) (10%) — The Swaen PlatinumSwaen Brown Porter — Grain — 400 EBC
350 g (0.77 lbs) (5%) — The Swaen BlackSwaen Chocolate B — Grain — 900 EBC
349 g (0.77 lbs) (5%) — The Swaen PlatinumSwaen Oat Flakes — Grain — 0 EBC

Hops (140 g) --> (used Saaz & Willamette because I had these as left-overs)
35 g (1.23 oz) (19 IBU) — Saaz 4.1% — Boil — 60 min
25 g (0.88 oz) (18 IBU) — Willamette 5.3% — Boil — 60 min
20 g (0.70 oz) (11 IBU) — Willamette 5.3% — Boil — 30 min
30 g (1.05 oz) (10 IBU) — Saaz 4.1% — Boil — 20 min
30 g (1.05 oz) (11 IBU) — Willamette 5.3% — Boil — 15 min

Miscs --> RO water with minerals
6 g (0.21 oz) — Baking Soda (NaHCO3) — Mash
4.13 g (0.15 oz) — Calcium Chloride (CaCl2) — Mash
5.17 g (0.18 oz) — Epsom Salt (MgSO4) — Mash
1.03 g (0.04 oz) — Gypsum (CaSO4) — Mash
1 g (0.04 oz) — Yeast Nutrients (WLN1000) — Boil — 15 min
2 g (0.07 oz) — Irish Moss — Boil — 10 min
15 g (0.52 oz) — Bourbon Oak Chips — Secondary

Yeast
0.6 pkg — Lallemand (LalBrew) Voss Kveik 77%

Fermentation
Primary — 33 °C — 7 days
Secondary — 30 °C — 5 days
Carbonation: 2.3 CO2-vol

Water Profile
Ca2+ 60
Mg2+ 22
Na+ 79
Cl- 90
SO4-113
HCO3- 200

Thanks all!

There isn't a ton in there that are the normal culprits of stuck mashes...did you crush your own grain? It looks like you have enough water as well.

How did the mash look? Watery or oatmeal/porridge like?

 

[IslandLizard]

I was unable to complete brew day because of a stuck mash.

A "stuck mash" is a fluid-mechanical issue, that can be resolved with some manual labor (stirring), and is not the end of your brew day.
I hope you didn't throw it out... it can be saved, even after 4-8 hours. It's just a long mash.

 

[hopjuice_71]

I've been using a Grainfather for ~6 years (many brews) and found early on it was prone to poor flow rates through the mash and, at worst, stuck mashes. I started conditioning my grain prior to milling and all these problems were solved, and my efficiency went up

 

[GillesF]

There isn't a ton in there that are the normal culprits of stuck mashes...did you crush your own grain? It looks like you have enough water as well.

How did the mash look? Watery or oatmeal/porridge like?

Porridge like

A "stuck mash" is a fluid-mechanical issue, that can be resolved with some manual labor (stirring), and is not the end of your brew day.
I hope you didn't throw it out... it can be saved, even after 4-8 hours. It's just a long mash.

I was afraid to burn whatever was at the bottom of the grainfather and damage the machine. In hindsight, this does not make sense because there was circulation, just not through the grain bed.

I've been using a Grainfather for ~6 years (many brews) and found early on it was prone to poor flow rates through the mash and, at worst, stuck mashes. I started conditioning my grain prior to milling and all these problems were solved, and my efficiency went up

How do you condition your grains?

 

[Knox]

Hey Gillie,

Sorry to hear your first experience wasn't a success!

As @IslandLizard mentioned, you can easily resolve this by stirring. An additional trick you can do is to have a pair of thick rubber gloves on hand, elbow long is preferable. Because sometimes when the stirring doesn't do it, you need to apply a bit of elbow grease and move the mash around so you free up your false bottom.

I don't know what size your grainfather is, but the preboil gravity here might be a culprit. The denser your liquid the slower it will flow through the false bottom. This is often a geometric issue of the false bottom, even professional ones have this issue. It comes down to the design of the false bottom and width of it. Next time, if you are able to, start with a larger preboil volume and simply boil it down till you hit your desired gravity.

 

[GillesF]

Hi Knox

I tried stirring but it did not really help. It was very difficult to stir with my plastic "spoon" though, so I will invest in thick rubber gloves.

The Grainfather is the classic G30 version. This was a small 3 gallon batch and I was almost at the limit of the Grainfather's capacity in terms of grain bill + water volume. How much extra preboil volume would you advice?

 

[Knox]

I tried stirring but it did not really help. It was very difficult to stir with my plastic "spoon" though, so I will invest in thick rubber gloves.

There you have two investments! Get yourself a mash paddle while at it, a nice hard wood or stainless steel one is a good investment.

The Grainfather is the classic G30 version. This was a small 3 gallon batch and I was almost at the limit of the Grainfather's capacity in terms of grain bill + water volume. How much extra preboil volume would you advice?

You don't have a lot of wiggle room. See if you can do 3.5 l/kg malt (this will give you a preboil volume of ~19.9L), currently you do 3.2 l/kg, stir while mashing and make some "deep cuts" while stirring. This way you might be able to fit everything in there.
If you ain't able to have everything in the grainfather, I would model your batch size for 10 liters so your malt bill is that bit smaller. Then you can add the extra water in the mash.

 

[GillesF]

Thanks for the great tips all!

 

[Knox]

Thanks for the great tips all!

Don't call them great tips before they have insured your success

Cheers

 

[Sammy86]

Porridge like

I have a Brewzilla 65L so similar machines...I would recommend a thinner mash...2 qts/pound of grain which it looks like you did.

I'm also a big fan of stirring the mash...i let the mash sit for 10 minutes then recirculate for 30 minutes and then give it a good stir...settle for 10 minutes, recirculate again for 30 minutes. Stir again, and settle before sparging/mashout.

All a learning experience and I am sorry that things didn't work out...i know it can be frustrating!

 

[hopjuice_71]

How do you condition your grains?

Here is an easy guide: Benefits of Wet Milling and Grain Conditioning | MoreBeer. Basically its just spritzing your grain with 60-90 ml of water before milling. It makes the husks more pliable so you can close your mill gap a bit and still not shred the husks. I also mill straight into my malt pipe then lower the malt pipe containing the grain slowly into the kettle containing water already at strike temperature. This approach pretty much eliminates dough balls and makes for a nice consistent mash with good flow properties. I routinely max out my system with ~7.5 kg of grain and I can still run my recirculation almost full blast.

 

[Jag75]

I agree with @Sammy86 , there's not a lot of grain that screams the need for rice hulls . I've had an issue once with my Grainfather when it came to stuck mash / sparge . It was my fault because I didn't use hulls when I had a lot of oats and wheat .

I think your mash was probably a little thick and the pump had a difficult time recirculating. One thing I learned by David Heath was not pushing down on the top screen too much when mashing. If you compact too much it struggles. Opposite for the sparge . When I mash I add grain, stir , add grain , stir until all grain is added. Then I do a final stir , add the top screen pushing down a little bit then pull up just a tad. Then start recirculating.

When I sparge I push the top screen down to compact the grains to get a slow even sparge. That process has worked really well for me.