Mashed High But thin.

[Grizzly299]

So I brewed a porter last weekend with an OG of 1.058 at 20 litres.

Mashed it high at around 68-69°C.

Unfortunately after doughing in I left the valves open and ended up with a mash thickness of about 4l/kg when I had originally intended 2.5 l/kg.

I also ended up with a hotter mash temp of 68-69°C because of the extra water. I as originally shooting for 66°C

So the beer has been fermenting away at 18°C or so and to my surprise is at 1.010! Which at first seems rediculous for the high mash temp.

However given that my mash was so thin I'm wondering if I reduced the beta amylase activity considerably.

I'm using Safale US-05 for this one.I don't think it's infected, it doesn't look, smell or taste as though it is.

Anyone else had this?

 

[Simonh82]

I don't think it's the mash thickness. Those kind of ratios are pretty common for people who brew in a bag.

US-05 is a pretty reliable yeast which can often give good attenuation. I'm still surprised that it has gone that low.

Are you confident in your thermometer and hydrometer accuracy?

 

[Grizzly299]

The hydrometer reads 1.000 in my tap water, at what is apparently 20°C according to my thermometer. Which would indicate that they are either both out or both bang on.

It's a strange one for sure.I had heard that US 05 had high attenuation but it just seemed odd to get over 80% with a high mash temp.

I was anticipating something like 1.014 or more.

 

[Flatline9]

I've used US-05 about 3 times and each time I've had a lower final gravity than BrewMate predicted by 0.002-0.004. So it could just be from the high attenuation I guess.