A few days ago, under a thread with the banner "Wine Aging" I made some
comments about the effect of temperature on the ability of airlocks to
protect wine. I promised to post more later.

Air locks are designed to be a constant pressure valve to protect the wine.
Of course during fermentation CO2 is given off, the pressure in the vessel
tries to go up and the excess volume bubbles out through the airlock.
Perfect. If the temperature of bulk aging wine increases, the wine expands,
pressure tries to goes up, and what ever is in the head space bubbles out
through the airlock. Fine. If the wine expands too much and all the head
space is expelled, then wine goes out through the airlock. Not so fine.
You can watch your wine you can prevent this.

But if the temperature drops too much, a different scenario takes place.
Outside air will bubble through the airlock into the carboy. If this
happens it is not a very good thing. So how much protection does an airlock
provide and how important is this?

I checked two types of airlocks. The S shaped airlock with three bubble
chambers on each side will hold 11 cc's of liquid when properly filled. The
3 piece cylindrical airlock will hold 9 cc's from bottom of the floating
valve to where liquid spills through the tube so it provides 9 cc's of
protection. (I did not have one of the S locks with one chamber on each
side free to test.) For this analysis I will use the 9 cc smaller airlock

The question now is how much of a temperature change will these volumes
protect against before air bubbles through the airlock. This is effected by
the volume of the wine and the starting temperature. I assume 25 deg C as
the starting temperature and determined the temperature drop the airlock
will protect against for different size carboys. I found the following:

Carboy Temp Drop
(US gal) (deg C)
1 9.7
3 2.2
5 2.0
6 1.2
10 0.8
12 0.7
13 0.6

This shows some pretty small numbers, but what are the restrictions of the
calculation.
1) I used the expansion of water. I found the expansion table for alcohol
but not for 13% alcohol, so I considered water to be a better estimate. I
suspect that wine will have more expansion and therefore less protection but
I can not say for certain.
2) I do not make a correction for expansion of the glass vessel but this
should be very small.
3) This is based on temperature changes of the wine, not the room. Over a
one day/night temperature cycle the room may change more than the wine.
(Thanks to Jack Keller for pointing this out.)

Now what does this mean? Standard airlocks will protect carboys of 5-6 gal
or smaller from temperature changes in a temperature controlled home and may
well protect the larger carboys. But if you are keeping wine in an
unairconditioned room or in a cellar that sees temperature changes of
several degrees C. You may want to take all this into account.

You should be aware of day to night temperature changes, changes associated
with cold fronts, and seasonal changes. Seasonal changes, though they may
cause the largest change will probably not be too important as there will
only occur once a year. Day night changes may not be important as the wine
may not change temperature fast enough to matter. But if it does it will be
catastrophic as it will happen 365 times a year. Changes associated with
cold fronts and heat waves may be the ones you really have to be concerned
about.

Ray Calvert

Hi Ray

Thanks for bring light to this risk. After reading your post I placed a 12
Gal DJ for cold stabilization. I left about and inch of headspace. The
temperature in my MLF area is 70F and in the garage it is 40F. I was amazed
at how much volume contraction occurred.

I am wondering whether I should now adjust the headspace or leave it for the
3-4 weeks it will take to cold stabilize?

Joe

"Ray" wrote in message
y.com...
A few days ago, under a thread with the banner "Wine Aging" I made some
comments about the effect of temperature on the ability of airlocks to
protect wine. I promised to post more later.

Air locks are designed to be a constant pressure valve to protect the
wine.
Of course during fermentation CO2 is given off, the pressure in the vessel
tries to go up and the excess volume bubbles out through the airlock.
Perfect. If the temperature of bulk aging wine increases, the wine
expands,
pressure tries to goes up, and what ever is in the head space bubbles out
through the airlock. Fine. If the wine expands too much and all the head
space is expelled, then wine goes out through the airlock. Not so fine.
You can watch your wine you can prevent this.

But if the temperature drops too much, a different scenario takes place.
Outside air will bubble through the airlock into the carboy. If this
happens it is not a very good thing. So how much protection does an
airlock
provide and how important is this?

I checked two types of airlocks. The S shaped airlock with three bubble
chambers on each side will hold 11 cc's of liquid when properly filled.
The
3 piece cylindrical airlock will hold 9 cc's from bottom of the floating
valve to where liquid spills through the tube so it provides 9 cc's of
protection. (I did not have one of the S locks with one chamber on each
side free to test.) For this analysis I will use the 9 cc smaller airlock

The question now is how much of a temperature change will these volumes
protect against before air bubbles through the airlock. This is effected
by
the volume of the wine and the starting temperature. I assume 25 deg C as
the starting temperature and determined the temperature drop the airlock
will protect against for different size carboys. I found the following:

Carboy Temp Drop
(US gal) (deg C)
1 9.7
3 2.2
5 2.0
6 1.2
10 0.8
12 0.7
13 0.6

This shows some pretty small numbers, but what are the restrictions of the
calculation.
1) I used the expansion of water. I found the expansion table for
alcohol
but not for 13% alcohol, so I considered water to be a better estimate. I
suspect that wine will have more expansion and therefore less protection
but
I can not say for certain.
2) I do not make a correction for expansion of the glass vessel but this
should be very small.
3) This is based on temperature changes of the wine, not the room. Over
a
one day/night temperature cycle the room may change more than the wine.
(Thanks to Jack Keller for pointing this out.)

Now what does this mean? Standard airlocks will protect carboys of 5-6
gal
or smaller from temperature changes in a temperature controlled home and
may
well protect the larger carboys. But if you are keeping wine in an
unairconditioned room or in a cellar that sees temperature changes of
several degrees C. You may want to take all this into account.

You should be aware of day to night temperature changes, changes
associated
with cold fronts, and seasonal changes. Seasonal changes, though they may
cause the largest change will probably not be too important as there will
only occur once a year. Day night changes may not be important as the
wine
may not change temperature fast enough to matter. But if it does it will
be
catastrophic as it will happen 365 times a year. Changes associated with
cold fronts and heat waves may be the ones you really have to be concerned
about.

Ray Calvert

Adjust the head space or blow it out with inert gas.

Ray

"Joe Ae" wrote in message
.. .
Hi Ray

Thanks for bring light to this risk. After reading your post I placed a 12
Gal DJ for cold stabilization. I left about and inch of headspace. The
temperature in my MLF area is 70F and in the garage it is 40F. I was
amazed
at how much volume contraction occurred.

I am wondering whether I should now adjust the headspace or leave it for
the
3-4 weeks it will take to cold stabilize?

Joe

"Ray" wrote in message
y.com...
A few days ago, under a thread with the banner "Wine Aging" I made some
comments about the effect of temperature on the ability of airlocks to
protect wine. I promised to post more later.

Air locks are designed to be a constant pressure valve to protect the
wine.
Of course during fermentation CO2 is given off, the pressure in the
vessel
tries to go up and the excess volume bubbles out through the airlock.
Perfect. If the temperature of bulk aging wine increases, the wine
expands,
pressure tries to goes up, and what ever is in the head space bubbles
out
through the airlock. Fine. If the wine expands too much and all the
head
space is expelled, then wine goes out through the airlock. Not so fine.
You can watch your wine you can prevent this.

But if the temperature drops too much, a different scenario takes place.
Outside air will bubble through the airlock into the carboy. If this
happens it is not a very good thing. So how much protection does an
airlock
provide and how important is this?

I checked two types of airlocks. The S shaped airlock with three bubble
chambers on each side will hold 11 cc's of liquid when properly filled.
The
3 piece cylindrical airlock will hold 9 cc's from bottom of the floating
valve to where liquid spills through the tube so it provides 9 cc's of
protection. (I did not have one of the S locks with one chamber on each
side free to test.) For this analysis I will use the 9 cc smaller
airlock

The question now is how much of a temperature change will these volumes
protect against before air bubbles through the airlock. This is
effected
by
the volume of the wine and the starting temperature. I assume 25 deg C
as
the starting temperature and determined the temperature drop the airlock
will protect against for different size carboys. I found the following:

Carboy Temp Drop
(US gal) (deg C)
1 9.7
3 2.2
5 2.0
6 1.2
10 0.8
12 0.7
13 0.6

This shows some pretty small numbers, but what are the restrictions of
the
calculation.
1) I used the expansion of water. I found the expansion table for
alcohol
but not for 13% alcohol, so I considered water to be a better estimate.
I
suspect that wine will have more expansion and therefore less protection
but
I can not say for certain.
2) I do not make a correction for expansion of the glass vessel but
this
should be very small.
3) This is based on temperature changes of the wine, not the room.
Over
a
one day/night temperature cycle the room may change more than the wine.
(Thanks to Jack Keller for pointing this out.)

Now what does this mean? Standard airlocks will protect carboys of 5-6
gal
or smaller from temperature changes in a temperature controlled home and
may
well protect the larger carboys. But if you are keeping wine in an
unairconditioned room or in a cellar that sees temperature changes of
several degrees C. You may want to take all this into account.

You should be aware of day to night temperature changes, changes
associated
with cold fronts, and seasonal changes. Seasonal changes, though they
may
cause the largest change will probably not be too important as there
will
only occur once a year. Day night changes may not be important as the
wine
may not change temperature fast enough to matter. But if it does it
will
be
catastrophic as it will happen 365 times a year. Changes associated
with
cold fronts and heat waves may be the ones you really have to be
concerned
about.

Ray Calvert

Joe, I ditto your thanks to Ray for the numbers. Ray is very good
with the science and math and I appreciate his input. We may disagree
on what it means under given circumstances, but I do not dispute the
physics or the math.

To your question, I would again say (as in the previous thread on bulk
aging) that if your wine was appropriately sulfited the increased
ullage from the wine's contraction will not matter to your wine. I
would leave it alone so that when you bring the wine back indoors it
can expand back to its former level. If you top up now, you will have
to later remove what you added or pay the consequences.

Jack Keller, The Winemaking Home Page
http://winemaking.jackkeller.net/

Ray, I echo Joe's thanks. The raw numbers ought to be a concern to
everyone who doesn't have a tight reign on the temperature of their
winemaking and storage areas, especially if you bulk age in containers
larger than 5 gallons.

I've been thinking about these numbers since you shared them with me a
few days ago. I kept thinking of your comment to me that they
indicate a larger airlock is really needed for larger containers. I
couldn't help but think of how we used to make our airlocks before
they were so readily and cheaply available and I think the old method
might serve anyone who thinks they might have a problem. All one
needs are an appropriately sized drilled bung, a length of 1/4 inch
tubing and a quart jar with lid--metal or plastic. You will need an
electric drill and probably some silicon gel caulking .

The bung must fit your demijohn or carboy correctly. Drill a hole in
the lid of the quart jar as close to the exact diameter of the 1/4
inch tubing as you can get. An inch or so from that hole drill a very
small hole. It need not be larger than 1/16th inch. If the lid is
metal, you can prick a hole in it with a small nail. Insert one end
of the tubing into the demijohn or carboy bung but do not push it past
the lower edge of the bung itself. If the fit is not tight, seal it
with the silicon. Trim the tubing so it arches upward and over to the
bottle (presumably sitting next to the demijohn or carboy), through
the larger hole in the lid, and about 2/3 down into the quart jar.
Fill the jar 3/4 full of 10% sulfite solution, tighten the lid, and
seal the tubing/lid junction with silicon. When the silicon dries,
you have an airlock that can withstand a dozen degrees of temperature
change either way.

Jack Keller, The Winemaking Home Page
http://winemaking.jackkeller.net/

Thanks for the kind words, Jack. It is not that we disagree, we are
interpreting the numbers based on different situations. The reason
information sometimes seems so conflicting on this site is that we are all
developing techniques that apply to the overall method each of us use. Take
one step from an overall procedure that makes good wine and try to stick it
into another method and it may not work. What is important is to develop an
overall understanding of what is going on so you can determine whether a
persons suggestion will work for you. If you protect your wine with good
levels of sulfite and let some air get to it, it may not matter. If you are
making wine with no sulfite, it may be disastrous. We just need to be award
of what is happening overall.

You are right about making your own airlocks and I have been planning to
make one for my 13 gal carboy. Just have not got around to doing it even
though I REALLY believe I should.

Ray

"Jack Keller" wrote in message
om...
Ray, I echo Joe's thanks. The raw numbers ought to be a concern to
everyone who doesn't have a tight reign on the temperature of their
winemaking and storage areas, especially if you bulk age in containers
larger than 5 gallons.

I've been thinking about these numbers since you shared them with me a
few days ago. I kept thinking of your comment to me that they
indicate a larger airlock is really needed for larger containers. I
couldn't help but think of how we used to make our airlocks before
they were so readily and cheaply available and I think the old method
might serve anyone who thinks they might have a problem. All one
needs are an appropriately sized drilled bung, a length of 1/4 inch
tubing and a quart jar with lid--metal or plastic. You will need an
electric drill and probably some silicon gel caulking .

The bung must fit your demijohn or carboy correctly. Drill a hole in
the lid of the quart jar as close to the exact diameter of the 1/4
inch tubing as you can get. An inch or so from that hole drill a very
small hole. It need not be larger than 1/16th inch. If the lid is
metal, you can prick a hole in it with a small nail. Insert one end
of the tubing into the demijohn or carboy bung but do not push it past
the lower edge of the bung itself. If the fit is not tight, seal it
with the silicon. Trim the tubing so it arches upward and over to the
bottle (presumably sitting next to the demijohn or carboy), through
the larger hole in the lid, and about 2/3 down into the quart jar.
Fill the jar 3/4 full of 10% sulfite solution, tighten the lid, and
seal the tubing/lid junction with silicon. When the silicon dries,
you have an airlock that can withstand a dozen degrees of temperature
change either way.

Jack Keller, The Winemaking Home Page
http://winemaking.jackkeller.net/