Topping up a Sanke fermenter to 15gal?

I really want to start fermenting in 15.5gal Sanke kegs. But if possible, I don't really want to modify them. I'm going to be doing 10 - 12 gallon boils, but I was wondering if it's possible to top up the water level in the Sanke fermenter to be about 15 gallons. I realize this wouldn't leave a lot of headroom, but maybe with a blow-off you could make it work. I would also imagine you'd have to start with some extra grain to compensate for the added water.

Does anyone do this? Is it even a possibility?

you would be wasting a lot of grain as you wouldn't be extracting all of the possible sugar out during mashing, it would work fine with extract though.

Are you trying to use the boil vessel as a fermenter or make 15gal batches? Not quite following you.

It is easy to do. Look into blending techniques. I am doing this on a beer in my fermenter right now, as well as doing a hop addition with the blending water.

there's another thread going on as i type about the logistics of 10 and 15 gal cornies. you should look into a conical and just bite the bullet.

You simply brew a higher gravity beer and cut it. Do not exceed a 1.060 initial beer and don't cut past about 25% of the blending water. Beersmith has a calculator for this.

I ferment in a 15.5 gallon keg. I harvest yeast and everything. I modified my keg dip tube but I don't think it is mandatory. I love fermenting in mine, even all under pressure. I have info in my signiature links.

McKBrew said:

Are you trying to use the boil vessel as a fermenter or make 15gal batches? Not quite following you.

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I'm using sanke keggles for my MLT and BK, and I'm trying to make 15gal batches. The question is, can I mash with a little extra grain to start with a higher gravity, and then top it off with more water in the fermenter to reach 15 gal and even out the gravity?

WortMonger said:

Look into blending techniques. I am doing this on a beer in my fermenter right now, as well as doing a hop addition with the blending water.

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That sounds like exactly what I'm talking about! Do you have any links that I could check out? a quick search came up with nothing.

Yes, it was in the link in my signature. Here you go. https://www.homebrewtalk.com/showpost.php?p=484466&postcount=41

WortMonger said:

Yes, it was in the link in my signature. Here you go. https://www.homebrewtalk.com/showpost.php?p=484466&postcount=41

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duuuuuh.....haha..whoops. Thanks man I really appreciate it! This is just what I was looking for.

No problem man, hey I'm in chat if you want to talk now.

Donasay said:

you would be wasting a lot of grain as you wouldn't be extracting all of the possible sugar out during mashing, it would work fine with extract though.

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I'm not sure what you are getting at, but it would be no more "wasted" sugars than a larger gravity brew would be. Could you explain a little further your statement?

unfortunately I'm at work, and It wont let me connect to the chat. But I'm sure I'll be needing your wisdom in the near future, so you may get a pm from me. Thanks again

No problem, I am always glad to help with the "out of the ordinary" on brewing. I do things a little different than most. What you are wanting to do is what the big boys do, so they prove it is possible (I know it is fizzy water, but it would be if they didn't blend it also).