Making your own glass of red (white or rosé) from scratch is easy and exciting. Once you make a couple of wine batches, even if they are small, you will begin to understand and appreciate any wine at another level. It would be safe to say that no wine expert is an expert until they have made their own wine. Also, when you taste your homemade wine, you will realize how many additives and chemicals they add to popular bottled wine. Your wine is going to taste very different and much more natural.
Indeed, the wine-making process changed dramatically over the last century. Most modern wine has lots of stuff in it that is not wine. We are going to leave it all out in this review. All the additives you will really need is wine yeast, some sugar and optional malolactic bacteria. You will also need a fermentation vessel and a fridge. A hydrometer is usually a must for winemaking, but we will learn to do without it.
A General Plan for Making Your Own Dry Wine
These are simplified winemaking guidelines. The detailed description of every stage is below:
- Pick the grapes when they are as ripe as possible, choose winemaking grapes, not the dessert ones
- Wash them properly under running water, remove any damaged or rotten fruit
- Separate the grapes from the stems and crush them. Use food grade gloves for handling the grapes
- Taste the juice. It should be very sweet. If it is not, add sugar to taste
- Measure the exact amount of yeast and activate it in warm water with some sugar
- Sanitize your fermentation container with a special compound and rinse with water
- Fill the fermentation vessel with the must (crushed berries and juice, or just juice) until up to ¾ volume of the container
- Secure the airlock on top of the container (a food grade glove with a couple of needle holes will do)
- Let the primary fermentation carry on (a lot of CO2 bubbles will be released)
- Separate the fruit from the juice no later than after seven days (whether it is still bubbling or not)
- When the active (bubbly) phase is over, do the first racking, leaving the sediment behind
- Continue to the secondary fermentation. Make sure a proper airlock is on (do not use a glove any longer)
- Taste your wine or take a specific gravity reading regularly until the sweetness is gone. You can stop fermentation if you like the taste, or you can continue.
- Do a second racking into a sanitized container, add malolactic bacteria, replace the airlock
- Let the malolactic fermentation continue even after the bubbling stops, then taste your wine
- If you are happy with the wine’s acidity, do the third racking and proceed with cold stabilization in the fridge
- After cold stabilization is complete, pour the wine into sanitized containers, leaving the sediment behind. At this stage the wine is ready for consumption or ageing
- Remember that sometimes fermentation can get “stuck”, sometimes wine can develop a smell of rotten eggs, and sometimes wine can taste like vinegar. This should not happen if you do everything correctly.
Picking the Right Grapes
The grapes you want to use are one of the traditional winemaker’s breeds. They should be gathered as ripe as possible to be at their maximum sweetness and minimal tartness. The grapes should have a good aroma.
Try tasting freshly squeezed juice out of your chosen grapes first. It must be sweet and very aromatic. Grapes that are intended for dessert, especially seedless white grapes, will hardly make a good wine.
Yeast is naturally present on the grape’s skin. Wine yeast in a sachet that you can buy in a winemaking store is a relatively recent invention. To be able to ferment grapes without adding any yeast, they shouldn’t be washed. Washing grapes will take away the natural yeast from the skins. However, for the purpose of home winemaking, washing is recommended. By doing this, we will make sure that our grapes are clean and free of any bacteria. If the grapes have an excessive amount of “wrong” microflora, the fermentation will go the wrong way. To be on the safe side, it is better to wash the grapes and supplement them with wine yeast. This way we will make sure that wine yeast is the strongest strain in our batch, and the desired result is guaranteed. Choose one of the most common and popular wine yeasts. Measure the exact recommended amount, use a scale.
Too much yeast may create an excessive yeast flavor. Too little yeast will slow down the fermentation; also there is a risk that it will never initiate or fermentation may stall. Mix the yeast you are ready to use with a small amount of brown sugar and warm water. Leave it to activate for approx. half an hour. If the yeast are producing foam (bubbles) by that time, it is alive and good for the fermentation.
After washing with pure water (no soaps!), separate grape berries from the stems. Place them into a clean bowl and crush well. Given their small amount, crush in small batches just using your hands (food grade gloves recommended). Crush only the amount of grapes that will fill your fermentation vessel to no more than ¾ by volume. The remaining space is necessary as the must will swell with the release of carbon dioxide.
It is of paramount importance that everything that comes in contact with the fermenting juice is clean. It should be not just clean, but hospital-grade clean. You can use a basic solution intended to sanitize fruits, or a special wine sanitizer. You can also sterilize glass vessels or bottles with steam. Throughout the whole process, we have to make sure that no foreign bacteria interfere. So, use clean utensils, a clean fermentation vessel, etc. Bacterial infections can cause wine to smell like rotten eggs, which may not be easy to eliminate. Use special compounds intended to sterilize the winemaking containers and utensils. They are not expensive and easy to use.
Winemaking Taste Formula
To better understand winemaking, it is important to know how the wine’s (or juice’s) taste and composition change throughout the process, starting from fresh juice and ending with actual wine. This formula will also help you choose the wine you prefer and stop the process at any stage.
Here are the winemaking stages and their corresponding flavor and composition:
- Maximum sweetness, zero alcohol, tart – Freshly squeezed juice
- Medium sweetness, medium alcohol, tart – Primary fermentation
- Low sweetness, high on alcohol, tart – Secondary fermentation
- Dry, highest on alcohol, tart – End of Secondary fermentation
- Dry, highest on alcohol, mellower – Malolactic fermentation
- Dry, highest on alcohol, buttery – End of Malolactic fermentation
- Dry, highest on alcohol, buttery, aged – After ageing phase
Adding Sugar to Your Must
Grapes are usually naturally sweet enough to make a good wine. However, adding sugar to the crushed grapes (juice) can be beneficial in some cases. If the grapes are not sweet or ripe enough, then adding some sugar (literally to taste) will help the fermentation. Adding sugar makes sense if you want to obtain wine with the highest possible alcohol content. In this case, it is important not to overdo it, because there is an alcohol limit above which the yeast will stop working. So in the end, you are risking getting a wine which is too sweet. Too much sugar in the must may also impede fermentation.
This is the most active part of the winemaking process, with lots of bubbling. It is important to remember that this is not the only fermentation required. Primary fermentation will produce approx. 70% of the target amount of alcohol. During this phase, our yeast will actively consume sugar, produce alcohol and carbon dioxide.
This phase will slowly roll into the second fermentation phase. As the sugar supplies deplete and the alcohol concentration increases, the fermentation will slow down. Red wines usually ferment best at about 70 F (21 C) and white wines at about 60 F (16 C). In any case, do not exceed 85 F (30 C) and do not go below 50 F (10 C). Oxygen exposure if tolerated. The duration of the primary fermentation depends on several variables: temperature, yeast concentration, sugar concentration, etc. It can last from a few days to a couple of weeks. It is important to keep a reasonably constant temperature during the fermentation. This will prevent stress on the yeast and getting the fermentation “stuck”. Stuck fermentations can be very challenging to restart.
Fruit in the Fermenting Juice
If you are making white wine and want it to look really “white” and transparent, ferment only grape juice without the seeds or skins. Any other wine can ferment together with the crushed berries during the first week of the process. After seven days, but not later than the primary fermentation is over, make sure to get rid of the fruit. One week is more than enough for the skins and seeds to give their color and other compounds (like antioxidants) to wine. After that, they may impede the wine’s taste and flavor. Without using any special tools (siphons etc.), just pour the fermenting juice through a sieve from one vessel to the other. Do not worry about the sediment, which is the lees or “retired” yeast. They will be taken care of a bit later. So, once again, if after five days of fermentation it slows down (very little bubbles formed), then get rid of the fruit. Another example, if after seven days the fermentation is very active, remove the fruit anyway. Just use a sieve and clean, sanitized containers.
Oxygen is welcome only in the initial stage of the active fermentation phase. It is an essential gas for the wine yeast to activate and multiply. However, after that, oxygen becomes an unwanted agent. Some wines may benefit from oxygen exposure during maturing, but this is rather an exception. To simplify things, we will simply always avoid oxygen exposure as much as we can. Saturation with oxygen that is necessary for the primary fermentation will take place during crushing. Another dose of necessary oxygen will be received when separating the fruit from the juice, as described above. If you don’t have an airlock, it is fine to use a regular food-grade glove to seal your fermentation container for a few days. Just puncture a couple of holes in it with a needle, so carbon dioxide has somewhere to go.
A glove is a good temporary solution, but it may let oxygen in once the fermentation becomes less active. A deflated glove will also indicate that the primary fermentation is over.
However, by the time the fermentation slows down and rolls into the secondary phase, get a proper airlock on.
Plastic Bottles and Containers
Fermentation can be done in plastic containers, but glass is always preferred. If you intend to consume your wine within a couple of months, then storing it in plastic bottles is also fine. However, for anything longer than a couple of months, a glass container is recommended. Glass is to be avoided if you are trying to stop the fermentation process while the wine is still actively bubbling.
Why Wine Can Sometimes Become Vinegar
Acetic bacteria, being a part of natural grape microflora, can break down alcohol and produce acetic acid. An approx. 5% solution of acetic acid makes vinegar, so it doesn’t take much of it to make wine irreversibly sour. We are not going to actively fight acetic bacteria during winemaking. We only need to make sure that they don’t have favorable conditions to reproduce and will remain dormant. Acetic bacteria are aerobic, meaning they need oxygen to remain active. All we need to do is minimize wine aeration, especially in combination with a warm environment. This is why during all the three fermentations the airlock will be on. Also, during storage, the amount of free air volume should be minimal.
Why Wine Can Develop a Smell of Rotten Eggs
Under certain circumstances wine can saturate with hydrogen sulphide (H2S gas), which will give it a smell of rotten eggs. This should not happen if you do everything correctly. This situation develops if you are not supplementing with yeast at all, only relying on the wild yeast from the grapes. In this case, the yeast may “overwork” and produce this gas. A similar situation can happen if you don’t put enough wine yeast, so read the labels and measure the yeast precisely. Another reason for H2S gas in wine is a bacterial infection or too high a fermentation temperature. Once again, it is very important to maintain cleanliness and a correct fermentation temperature range.
There are several basic solutions to eliminate the smell. Do a couple of rackings, making sure the wine aerates sufficiently (splash it around the container walls). Also you can try leaving the wine container open for 7-10 hours without an airlock. If this doesn’t help, use a supplement called gelatin finings or bentonite.
Once the primary fermentation is over, the next “quiet” stage begins. This is easier to spot by very little or no visible gas leaving the liquid. At this point do the first racking. This simply means transferring your wine-to-be into another clean container and leaving the lees (the “retired” yeast) behind. The active yeast will remain in suspension, so fermentation will continue. The secondary fermentation will make up the remaining 30% of the alcohol. As mentioned above, red wines usually ferment best at about 70 F (21 C) and white wines at about 60 F (16 C). In any case, do not exceed 85 F (30 C) and do not go below 50 F (10 C). Oxygen exposure is to be avoided during this phase.
This phase is intended for dry red wines and some of the dry white wines (Chardonnay). In the absence of sugars, wine will likely taste tart, a bit like an unripe green apple.. This is due to malic acid, which is the primary acid in grapes. Malic acid literally means “apple acid”. Its sourness is not very pronounced when grapes are ripe and sweet. However, as the sugars convert into alcohol, the wine begins to taste tart.
Malolactic fermentation is intended to convert a sour malic acid into a mellow and buttery lactic acid. This process will usually occur naturally and may last a couple of months.
Alternatively, malolactic bacteria can be added to wine to initiate or facilitate this phase. The malolactic fermentation temperature should be in the range 60 F – 77 F (16 C – 25 C F). The malolactic fermentation is best done after the secondary fermentation has already finished. Remember to taste your wine first, perhaps you may want to skip the malolactic phase entirely. If not, add a recommended amount of malolactic bacteria (as per the maker’s instructions). Make sure the airlock is on, carbon dioxide will be released during this stage.
During the malolactic fermentation, total acidity is reduced as per the below formula. A release of CO2 into the atmosphere means that the resulting solution is less acidic.
C4H6O5 = C3H6O3 + CO2
The wine’s contact with oxygen from the air is not desirable. Alternatively, you can inoculate your wine during the first racking, after the primary fermentation has completed. The rule of thumb is the less remaining sugar, the better. However, some residual sugar, like during the secondary fermentation phase, is acceptable. Keep in mind that if you skip the malolactic phase during the winemaking, it can spontaneously start later, when the wine is already bottled.
Racking is simply transferring clearer wine material to another container, while leaving behind the sediment and anything that floats. For a small amount of wine, no special equipment, like a siphon is needed. The less tools and utensils you use, the less chance there is to contaminate the wine. At the time of the first racking, there should not be any fruit floating on top. All it takes then is to pour the wine from one vessel to another leaving the sediment. Cleanliness and minimal exposure to air is very important during racking.
When to Start Tasting
Once you get rid of the fruit, you can begin tasting the wine. It is a good idea to taste it regularly to know where you stand in order to keep the outcome under control. It is very possible that the taste you are looking for will develop before the secondary or malolactic fermentation is complete. For example, you want the wine a bit sweet and sour-ish. In this case, you will probably stop somewhere during the secondary fermentation. If you want you wine dry with some brightness, you will probably let it complete the second fermentation and stop somewhere during the malolactic phase. Just make sure you use a clean utensil for the tasting and reduce the contact time with air to a minimum.
Regular tasting will also alarm you if the fermentation gets “stuck”. If you have a hydrometer, take a reading each time you do the tasting. No change in the specific gravity reading over a long time will indicate that the fermentation is complete or “stuck”.
Tasting or rather “smelling” your wine during the fermentation will also help detect a smell of rotten eggs, which comes from hydrogen sulphide (H2S). If you sense this in your wine, the faster you act, the better. See above how to tackle this situation.
A rapid change in temperature, the presence of certain bacteria, a lack of oxygen and other factors can cause fermentation to stall. For example, you are at the secondary fermentation phase, and you don’t see much bubbling going on. This is normal if the sugar content continues decreasing while the alcohol content keeps increasing. However, if these two parameters don’t change over a few days and the wine is still sweet and low in alcohol, then the fermentation is “stuck”. You can determine the alcohol content by tasting your wine regularly or by taking a specific gravity reading using a hydrometer. If the numbers are not changing, but the wine is not ready, then it got “stuck”. What can you do to restart it? There are a few methods used by professionals, that includes supplementing the wine or restarting it all over. These methods are not covered in this article. One of the basic things you can do to restart the fermentation is stirring the wine to let some oxygen in and to agitate the yeast. Also, you can bring your fermentation container to a slightly warmer area.
Why and How to Stop the Fermentation
You can stop any type of fermentation at any time you like by cooling your wine down in a fridge for approx. 21 days. However, it is not guaranteed that the fermentation will not restart at least to some degree once the wine is out of the fridge. It will also take some time for it to stop while in the fridge itself. So, if the wine is actively bubbling, even while its cooling down, high pressure can develop. Therefore, if you choose to stop fermentation early to make a bubbly wine, it might be a good idea use a plastic bottle (intended for carbonated drinks) in order to cool the wine down. Having a safety valve installed on the bottle is very much recommended. If you choose a glass vessel, then make sure to keep the airlock on. Never seal wine that is still fermenting in a glass bottle!
Why stop the fermentation in the first place?
Example 1: Making a Sweeter Wine Reasonably Low in Alcohol.
In this case, you can do the first racking and then cool the wine down in the fridge for at least 21 days. If you cool it down in a closed container (never a glass one), it will most likely become slightly carbonated. After 21 days, you can do another racking to get rid of the sediment.
Example 2: “Freezing” the Taste You Like
You are in the malolactic stage and want to “freeze” the current taste that you would like to keep. If you carry on with the fermentation, the wine will become more mellow and buttery. If you want to keep it a bit more tart, put the wine in the fridge. After 21 days, transfer to another container to remove the sediment.
Once the fermentation is stopped by chilling for at least 21 days, it will usually not restart. However, if you stop the fermentation, it is best to avoid keeping the wine in sealed glass containers for another month or so. This is just for safety in case the fermentation restarts, and pressure builds up. During the three weeks in the fridge, if the wine is clear enough, then it is completely safe for consumption.
This phase will slightly reduce the wine’s acidity due to the precipitation of tartaric acid salts. Place your wine in a cold environment (slightly below 4.5 C or 40 F) for approx. three weeks. A colored crystal-like sediment, which is potassium tartrate, will collect in the bottom. During this phase, the wine will become clearer. Also, the remainder of the yeast will go dormant and precipitate, along with the remainder of the particles. This all will ensure that no fermentation will restart. Make sure to minimize contact with air during this phase. Airlocks are not needed, but it is best to fill the containers to the top and close the lids tightly. After the cold stabilization is complete, do a final racking. After that the wine is ready for consumption or bottling. For home winemaking purposes, the cold stabilization phase can be skipped entirely. However, in this case the wine needs to be consumed sooner rather than later. Also, if this phase is skipped, precipitation of salts can happen later on, if the wine is cooled down.
Sediment in Wine
Sedimentation will occur at least twice during the winemaking process. Most of the sediment will precipitate during the primary fermentation. This sediment will almost entirely consist of lees or “retired” yeast and, perhaps, some tiny grape pieces. It will be removed during racking.
Another sedimentation will happen during the wine’s cold stabilization phase. Potassium tartrate mixed with the remainder of dead yeast and other particles is what usually precipitates during this phase. Often the sediment comes in crystals.