Fermenter headspace, rising cap

[jesseb]

Next grape season is getting close so my planning phase is in full swing. I’m currently wondering if my fermentation vessel is large enough to accommodate the whole batch of red grapes, if the cap will rise during fermentation. I get the grape must in plastic tuns, filled to the brim. Last year I split the batch between this and a stainless fermenter, so both were filled to about half. I would prefer to have the whole batch in the stainless and get rid of the plastic (also temp control is only possible on one vessel, not both).

But this means that there will only be about 5cm/2 inches left of headspace, so the cap is probably going to rise against the top. The lid is heavy enough to stay put (or I could weigh it down a bit). This means the cap cannot rise as much as it would freely, and it being more submerged in wine. My concern is clogging the blowoff hole for the airlock, that’s why I just lay the lid loose instead of bolting it down. As the cap is relatively dry, I’m not worried about overflowing liquids/wine.

The batch is 30L and the fermenter is 35L, so 5L left of headspace. The heigth is 35cm, thus the 5 cm headspace.

Any thoughts on this?

This is the stainless fermenter:

 

[crushday]

My current fermentors are 55gal food grade plastic drums. I frequently put 50 gallons of must in each during fermentation. Always, the cap gets to the top ridge. Occasionally, the cap goes a little higher. When it does, I weight the lid down and it keeps it from spilling over. At the end of a ferment, using 5 fermentors, I usually have a dustpan of skins to clean up which can and do fall out during punching. I consider this a win!

If you follow your plan, I would weight down your lid once the cap gets near the top.

You never gave any indication of your batch volumes. What is the capacity of that illustrated stainless vessel?

 

[jesseb]

You never gave any indication of your batch volumes. What is the capacity of that illustrated stainless vessel?

You’re right, edited my initial post. Batch is 30L and fermenter is 35L. Your batches are a lot bigger, and comparably less headspace (50/55gal vs 30/35 liters).

It's going to be a mess but that’s fine. Last year I put the fermenter in a bathtub to be able to ‘easily clean’ everything. The red stains in the tub are still there. No more fermentation inside the house this year.

 

[Jim Welch]

I’d say that’s not enough headspace but crushday’s setup is proportionally less than yours, 10% vs 16.7% headspace. Different yeast strains have different foaming properties so I imagine if you use a low foaming yeast you might get away with little or no overflow.

 

[crushday]

You’re right, edited my initial post. Batch is 30L and fermenter is 35L. Your batches are a lot bigger, and comparably less headspace (50/55gal vs 30/35 liters).

It's going to be a mess but that’s fine. Last year I put the fermenter in a bathtub to be able to ‘easily clean’ everything. The red stains in the tub are still there. No more fermentation inside the house this year.

Also, during primary fermentation I wouldn't be concerned about locking everything down - you need oxygen to help the yeast. Do you perform a MLF? If so, that's when you'd lock down and use the airlock.

If you do happen to employ your tub as the fermentation space, just put a plastic tarp between the tub and the fermentation vessel. And, a little PBW should do the trick getting last years stains out. If you don't have or can't get, PM me your address and I'll post you some. And, I'm aware you live in Amsterdam - love that place...

 

[jesseb]

I do, but not entirely sure about when I want to start MLF yet. Last year I did it after the pressing in a demijohn, with rubber stopper and airlock but I’ve read somewhere it is also possible to do it at the same time as the AF. Alcohol is not beneficial for the malo culture so it has a head start the first days or something.

Thanks for the offer, but I do have some PBW as I also brew beer. Never thought about using it for cleaning sinks/bathtubs though. Going to give it a try.

 

[hawkwing]

My current fermentors are 55gal food grade plastic drums. I frequently put 50 gallons of must in each during fermentation. Always, the cap gets to the top ridge. Occasionally, the cap goes a little higher. When it does, I weight the lid down and it keeps it from spilling over. At the end of a ferment, using 5 fermentors, I usually have a dustpan of skins to clean up which can and do fall out during punching. I consider this a win!

If you follow your plan, I would weight down your lid once the cap gets near the top.

You never gave any indication of your batch volumes. What is the capacity of that illustrated stainless vessel?

How many lugs fills up a 55 gallon fermenter?

 

[crushday]

As a general rule, three lugs (36# each) = 10 gallons of must = 6 gallons finished wine, with a little for topping up.

Using those measurements, fifteen lugs (crushed) would be 50 gallons. Keep in mind that a 55 gallon drum is actually closer to 60 gallons, which gives you approximately 17% headroom for the rising cap. Sometimes I have to weigh down the lid (a case of wine works great) of the drum to keep from spilling over but this is very seldom.