Skip to content

Cold Stabilization

2010 January 5

I wrote this in August of 2007. Much has changed since then.
Edited 1/10

After we know that Malolactic Fermentation (MLF) is complete, the first dose of K meta will be made at this time ¼ teaspoon level baker’s teaspoon, per 5 gallon carboy. Having done this racking, the wine will be topped off to one inch below the bung. No other air space is allowed. You will then move the wine into the cold for the winter. This is called cold stabilization. How cold. Very Cold!!!! We would love the wine to stay at 25 degrees for the winter but we know that this will not happen. However, the wine will not freeze before 24 degrees to be safe. But reposts have it not freezing until 13 degrees. In any case, what you will do is leave a gallon water jug ¾ full next to the wine. If that water freezes then we will monitor the temp of the wine each day during the cold spell. You would be surprised how cold it will need to get to even freeze the water. The carboys will be placed on wood or card board or left in their crates. Not on the cement. We don’t want moisture from the floor to freeze the bottom of the carboy and if you were to move it the bottom might crack off. After the winter, usually in March, the wine will be racked again using the stick and the hose. It will be given another dose of K meta, ¼ teaspoon per five gallons. At this point the wine really needs to be bulk aged or go in a barrel, or bottled and drunk with Easter Dinner. But remember, you are drinking a teenager. I know some of you like teenagers….., but I digress. In any case, the teenager, in what ever form it is, in a bottle, in a barrel, or in the carboy needs to be kept at 55-65 degrees for its entire life. We should monitor the wine as it progresses and make adjustments to acid, tannin, and other adjuncts as could become necessary. The airlock must have either a solution of K meta or vodka. Those with a few carboys are advised to just use vodka. It won’t freeze and it is sterile, and will not lose its effectiveness, however it might evaporate sooner. For topping off the carboys after Racking a good quality commercial wine can be used. Those with more will have extra for topping.

What has changed ? The grapes have. Back then we were accustomed to adding lots of tartaric acid to raise the Tartaric Acid (TA) and lower the PH. Central Valley Grapes and Lodi are hot weather grapes with low acid and high PH numbers. Not great for taste and not good for long term aging without worry of microbiological spoilage. Now, since we are using Northern and Coastal grapes we are finding much better PH numbers and reasonable TA acid numbers. The result is we are not adding tartaric acid to many batches. Take for example a central valley grape with a ph of 3.9 and a TA of .40 (typical) you would need to use 11 teaspoons of Tartaric Acid in one carboy to raise it to .70, and that is what we did as a matter of practice. We got the PH down to a reasonable, safer level and we had a reasonable TA for a red. Except for one thing, the Acid is not stable. It will drop out in the form of bi tartrate crystals in your bottle if the wine gets cold. So, we lowered the temperature of the wine to drop out the crystals before the spring racking. Then they were eliminated forever to the temperature we subjected the wine to during the winter. The result was a TA that got lowered usually back down to .60 and the PH remained lower too. But what if we have perfect numbers? What if we don’t need to add acid? Do we want to lose the acid we have by exposing the wine to very low temperatures? The crystals are much less a problem because we did not add any. SO why do it? Well to answer that first you will get some crystals out at 35-40 degrees. So if you wine is not stored at lower temperatures again you will never get crystals in the bottom of your bottles. I like whites chilled so I think a white can use a cold exposure to 30 degrees. Also, whites have more acid to begin with and exposing it to cold will mellow out that acid. But do we want to lose it?

Pinot Grigio can have a TA of .90. This year we added a touch of acid to the Petite Syrah, we are letting taste guide us but the PH numbers were not that great, but certainly not a problem.  Are there other advantages to Cold Stabilization?  The cold helps with clearing and makes for compact lees so racking is easier.  Now think about this, most boutique wineries in Napa don’t have a cold winter. Maybe only as low as 40.  No more cold stabilization than that is used.  And yes, your 150.00 dollar Napa Cabernet Sauvignon that you open may have a few crystals at the bottom of the bottle.

Guess what?  No one cares, not even the Judges.

What am I doing with mine?  Mine is in the garage.  On Saturday it was 19 degrees outside and 36 in the garage.  Cold enough for me.  I am sure you are familiar with the expression, “The Art of Making Wine”.  The major subtext that often gets over looked is, “The Art of the Acid”.

Read Jackish, “Modern Winemaking”, it is one book you must read.  Buy a used one.

18 Responses leave one →
  1. Steve the Barbarian permalink
    January 11, 2010

    Besides the precipitation of the TA from the cold, please list the other benefits of cold stabilization.Also what is the history of CS. IS it a more modern procedure or have the wine makers been doing it for years?

    How do the large volume producers cold stabilize?

  2. genefiorot permalink*
    January 11, 2010

    Besides the precipitation of the Bi-tartrates ( not TA ) not many other benefits at all. Spring time racking will be easy as lees will be very compact. Historically the observation of crystals ( wine Diamonds ) led to realize they formed when the wine got cold. Not a problem for many winemakers. Most Natural Cellars never go below 55 degrees anyway.

    Large volume producers that do major acid adjustments with low quality grapes use glycol chillers in which a wine is sent through a chilled piping system that can stabilize a large tank in 24 hours.

    Have you ordered the Jackisch Book Yet?

  3. Steve the Barbarian permalink
    January 15, 2010

    Thanks for the response Gene! I will purchase a PH meter and the TA kit ASAP.

  4. AlbanyCellarRat permalink
    January 16, 2010


    When I began winemaking, I would always cold stabilize my red wines. I felt that the wines tasted fresher and that the process helped with clarification. Cold stabilization isn’t just to reduce acid and to avoid unsightly tartaric precipitation. It also has other benefits. A lot of winemakers discourage cold stablilization for a number of good reasons.

    Our fine president, NOT Obama, I said fine president, Marty Yule has recommended a book authored by Philip Jackisch. The book is called Modern Winemaking. The book is packed with a lot useful information and in my opinion should be included in your wine library.

    On page 161, Jackisch states the following:
    “Many winemakers do not cold-stabilize red wines, apparently believing that they will never be subjected to cool temperatures. Most red wines not cold-stabilized, however, will eventually deposit tartrates in the bottle. Homewinemakers may choose to ignore these deposits, but the settling out of tartrates during cold stabilization can remove bitter-tasting oxidized pigment particles and both clarify a wine and improve quality”

    Personally, I agree with the above. However, I no longer cold stabilize my reds because I have my wine in tanks and do not have them equipped with the glycol cooling jackets. I could drain the tank and place the wine in carboys, then to the cold garage, but I am not that motivated.

  5. genefiorot permalink*
    January 16, 2010

    Jackisch said “but the settling out of tartrates during cold stabilization can remove bitter-tasting oxidized pigment particles and both clarify a wine and improve quality”

    I am sure Steve the Barbarian will like this part. But not much is really ever said about that positive effect. However I don’t think you need to subject the wine to 20 degrees for 2 months to achieve that effect. I think 30-40 does just fine.

  6. Steve the Barbarian permalink
    January 16, 2010

    Yes Steve does like this part.And guess what, I don’t rack before I cold stabilize. I rack after. OK guys – go ahead and tear me apart!!

  7. genefiorot permalink*
    January 16, 2010

    OH NO !!!!!!! Please say it ain’t so Joe! Is this a function of total laziness or do you have a strategy?

  8. Steve the Barbarian permalink
    January 16, 2010

    It started out as lazyness but then my 07 Zin turned out extremly well (beginners luck). At the last 08 Christmas Party Paul suggested that I enter it is a competition but most of it was already gone. Here is my theory:

    The character of the wine comes from the grape skins. The sediment is what is left of the skins after pressing. The longer the wine can be exposed to the sediment the better for flavor.

    After months of cold stabilization the sediment is like a clay at the bottom of the carboy making racking easier. The wine is super clear, in fact I racked again a month later and there was almost no sediment at the bottom of the carboy. This year I may not rack the second time. Also because the sediment becomes so thick it is more difficult to disturb while racking.

    Also I feel that the wine finished what it had to do in the carboy while in the boiler room. Keeping it very cold until it goes in the barrel allows for the exhange of chemicals from the sediment but will inhibit anything else from going on biologically.

    Look at me, if you read the above it almost sounds as if I know what I am talking about but it is really just guessing with no foundation in any kind of clinical testing.

  9. genefiorot permalink*
    January 16, 2010

    OH Boy Steve we will have to get out the books for this or just call you lazy and leave it at that. lol One thing that saves you is your gross lees in the carboy after pressing are very reduced using our method of pressing. Believe me this is saving you but it is not a surefire method for not racking after MLF
    By the way, you are not the first person I ever met that does this. But that was not added to make you feel better. LOL Roll the Dice!

  10. AlbanyCellarRat permalink
    January 17, 2010

    I know Gene’s method of pressing probably gets rids rid of more gross lees than other methods. And I assume that you settled for two days after pressing then racked again. That is what I do. You may be alright, but you are rolling the dice.

    Good luck.

  11. genefiorot permalink*
    January 17, 2010

    YOU ASSUME COUNSELOR? Am I hearing correctly? eeeeeeeeeeeee o boy.

    ALL RISE !!!!

    Will the Defendant Steve the Barbarian approach the Bench.

    Well then I assume the Cellar Rat from Albany is the defendant’s counsel in the matter?

  12. genefiorot permalink*
    January 17, 2010

    I see a subpoena in your future.

  13. Steve the Barbarian permalink
    January 17, 2010

    Make sure you have a good attorney who can litigate because generally in cort I crap all over the plaintiff’s attorney. They wish that they never put me on the stand.

  14. January 17, 2010

    OK so if I am settling out the lees anyway through CS why is that a bad thing? If I over do it I can always add some TA later.

  15. genefiorot permalink*
    January 17, 2010

    Ok so here we have the situation.
    Process one: After 48 hours the wine is racked off the lees and inoculated with ML Bacteria.
    Process two: ML Bacteria is introduced in the vat 48 hours prior to pressing and a careful pressing with screens and multiple strainers are used to put the wine in carboys minimizing gross lees. Wine is then racked at the completion of MLF.
    Up to 3 months.
    Process Three Wine is kept on the lees until March or April 5-8 Months then racked for the first time. ( Barbarian’s Method)

    Why do winemakers rack so early in Process one? They feel that any large amount of lees can cause a problem with off odors, off tastes, and the formation of H2S when the yeast dies.

    Why do winemakers rack the first time after MLF. This is what we do. First if we racked after 24-48 hours we would remove all the gross lees but also remove nutrients the ML Bacteria needs to accomplish its task. Thus we would be forced to add more nutrients to the wine after the racking at that time. Also everyone would have to inoculate their own carboys with ML bacteria. And finally there is not enough room to press the wine and pump it into another tank and settle it there for 24-48 hours and then have everyone return to fill their carboys two days later. So that is the compromise we make. Again many winemakers will not rack until after MLF is complete regardless of our reasons.
    Pressing the way we do does eliminate much of the lees so I am relatively comfortable with our process. Given a choice, time , energy and youth,and facility, I would opt for Process 1
    On the other hand I cannot condone process 3. First there is no good reason to stay on lees that long. There are no benefits. I am not talking about fine lees that are usually left after the first racking. So this is about being risky. Nothing more. Laziness is a perfectly reasonable excuse. But to justify this process as a good one will need quite a lot of back up that I do not believe you can find accepted sources to make your case. As I have mentioned before it is our process 2 (the pressing method) that I believe is saving your ass.

  16. AlbanyCellarRat permalink
    January 18, 2010

    I do process #1. The only thing I would add is that if I press when the wine is not completely dry (which usually isn’t my practive), I will place it in the tank, let fermentation complete, then rack off the gross lees.

    This I learned from Gene. I think you if you rack the wine off the gross lees before primary fermentation is completed you risk a stuck fermentation.

  17. genefiorot permalink*
    January 18, 2010

    Yes!, No 1 us the safest, So by default it is the best. And until there is a good reason to not do the safest procedure we DO IT! no? sure? yaaaa and then…..
    I have to laugh. As focused I have been on the MLF I have to admit I have been ignoring the residual sugar after pressing. AND I can safely say the wine in the carboys probably have residual sugar that still needed to ferment. BUT I know this , this is why we keep the temperature at 74 to complete the processing of the last sugar. OH yea MLF too.

    Thank you Counselor for the compliment. I am actually taken back that you remembered that. And yet I am reminded, how and why, I make the wines I make.
    Technically it is simple. Look at it this way, I am a yeast , I am tired because I have been around drunks for days on end and you are asking ME , YO finish up the sugar? And we are taking the food with us too. YO, You YO ,om goin home and mess with your woman before I finish up anymore sugar = residual sugar. food for brett?, food for volatile acids? ya

    So the difference is that most of these guys have to have all this winemaking thingy happen on a weekend. So totally fermenting out until the cap starts to sink is not a viable method for these constraints. Which is the way I think we should go and don’t because ya we’re at minus a 1/2 We can press , We have to press it is Sunday duh. But it hurts not to let it go to Wednesday or Thursday of the following week. THEN the cap has sunk. Press with care. and then in 48 hours you can rack off the lees with confidence, residual sugar is gone.
    Stuck fermentation, I know people get them but I have no idea how it is possible if one follows prudent procedures. Even so I have during the CRUSH 80 grams of THE ORIGINAL ‘PRISE DE MOUSSE’
    AS insurance. And I cannot imagine having a 25+ brix must and getting to >50ppm of sugar in 7 or 8 days. when 15 would be more like it. Sonny’s soccer tournament can live for another day We did what we had to do with the Beckstoffer Georges III God as my Judge. I would have done it myself if I had to.
    Now interestingly 2007 was the only time in my wine making experience I racked off the lees. And it was in 09 this Late Summer I had a slight problem with a 07 Suisun Cab Sav. in the barrel prior to bottling in November.

    Residual Sugar? COuld be.

  18. Gene Fiorot permalink*
    March 12, 2010

    At the end of the day Cold Stabilization is an important tool to reduce acid, knock out bitterness, and lower ph in some cases. Its benefits surpass just getting rid of wine diamonds. And compacting lees making racking easier.

Leave a Reply

Note: You can use basic XHTML in your comments. Your email address will never be published.

Subscribe to this comment feed via RSS

You can add images to your comment by clicking here.