Category Archives: enology

Making A Yeast Starter

Why make a starter?

You can get good results from wine yeast by just sprinkling a newly opened packet directly onto your must. There are times, however, that you really ought to use a starter. Yeast become active and start reproducing much more quickly and reliably in a starter, so in difficult (for the yeast) situations, like trying to restart a stuck fermentation or if you doubt the viability of your yeast (because it’s been sitting on a shelf for years, for example, or you ordered it during a freak heatwave and it may have gotten cooked in a delivery truck somewhere), a starter is worth the effort. You may also want to make a starter if you need your yeast to dominate the must quickly. Maybe you don’t like to use sulfite or you had to leave your must sitting for longer than you expected before you could pitch your yeast.

Some people use starters routinely. This is probably unnecessary, but it doesn’t hurt.

How do you make a starter?

First, you should rehydrate your yeast according to the directions on the package.

Rehydrating Yeast

In the photo, I’ve sprinkled the yeast into a quarter cup (about 50 ml) of warm water and let it sit for five minutes. Coming out of dormancy is stressful, and a lot of yeast cells die. Warm water, with no additives like nutrient or sugar, is the least stressful way to do it and results in the largest population of live yeast.

While you’re waiting, dissolve a tablespoon of sugar (12 grams) and a pinch of nutrient in a cup 2.5 fluid ounces (75 ml) of water. Once your yeast is rehydrated, add it to the sugar water. You should see signs of activity in less than an hour.

After 30 minutes, bubbles appear on the surface of the yeast starter. They are predominantly in the center and cover about 25% of the surface.

In about four hours, it should be active and foamy and you can add it to your must.

The yeast starter is four hours old now and bubbles cover the surface.

You can let it continue for a up to a day, but there is probably no advantage in it. Any benefit from additional growth will be offset by having your must sit around with no yeast in it. If you do want to let the starter grow for a while, maybe because you made the starter before you prepared your must, then keep an eye on it every few hours and add sugar water, 1 tablespoon (12 g) sugar to each half cup (120 ml) if activity subsides. If you made the starter to restart a stuck fermentation, it’s better to add must to the starter, in a new fermenter, gradually.

Update 7/13/2010 – Changed the recommended sugar concentration

My original recipe for a starter was about 5% sugar, but I now use 10%. That’s about two tablespoons (24 g) of sugar to each cup (240 ml) of water. The yeast will have something to chew on either way, but 10% sugar is about halfway to the 20% or so common in wine musts. That makes it less of a drastic change. It means the starter might take a little longer, and can be left a little longer, before pitching.

Making Wine From Grapes With (Almost) No Equipment

Don’t buy the expensive equipment

I buy wine grapes through my local homebrew shop in 100 lb lots, which is enough to make five or six gallons of wine. They take customer orders, arrange to buy the grapes from growers, and provide the use of their equipment. They will do all the work, so I can just show up with two empty 5-gallon carboys and go home with two 5-gallon carboys partially filled with juice. I like making wine, though, so I usually roll up my sleeves and go to work. I lug boxes of grapes to the crusher-destemmer, turn the hand crank to crush the grapes, put the crushed grapes into the press, collect the juice, then go home with two 5-gallon carboys partially filled with juice.

Reds can be alluring, but whites are easier

Red wine is all about the skins and, unlike kits, you can ferment a must of crushed grapes (in which case you’ll be taking home a primary fermenter full of crushed grapes rather than carboys of juice). This is a great way to make red wine, but there is a problem when it comes time to press. My local homebrew shop will let you use their press, for no additional charge, but you have to bring your fermenter back to the shop to do it. That’s a hassle I’d rather avoid, so I usually buy white wine grapes.

An easy way to make it good, and a hard way to make it better

Red or white, it’s a good way for amatures to make wine from grapes. Crusher-destemmers and presses are expensive, so the use of their equipment makes this a good deal. And making wine from grapes is easy; I’ve made very good white wine by just pitching yeast into the juice, with no adjustments at all. It’s an easy process with good results, but it also reinforces my decision to grow (some of) my own. I can’t help wondering how these grapes were grown. Were they harvested at their peak or at a convenient time for the grower and retailer? How much time had passed from harvest to crush? If the wine is good, how much better could it be if I harvested the grapes at their peak, processed them, and pitched the yeast all in one morning? My bonsai vineyard may produce enough grapes this year for me to find out!

Cherry Wine Recipe: Sugar and acid

Too much acid, but I don’t dare neutralize it

I pressed the cherry wine four weeks ago, and looked in on it yesterday. It’s had time to settle, and the clear wine has a lovely dark color. It tastes tart, though, and when I measured the total acidity (TA) I could see why. It was 11 grams/Liter, as tartaric, and in a dry red wine it ought to be more like 6 or 7 g/L. Usually TA and pH move in opposite directions; if your TA is high, all that acid pushes the pH low. This time, however, the pH was 3.76, which is higher than the 3.2 to 3.6 optimal range for red wine. The problem with a high pH is that it makes a wine vulnerable to microbes, and it may not age as well. You can remedy a high pH by adding acid. If the TA is too high, you can neutralize some of the acid, as I did recently with my oregano wine. But how do you deal with too much acidity and a high pH?

So I’ll bring the wine into balance by sweetening it

The high TA affects the taste, so the way out of this dilemma is to improve the taste without affecting the acidity. That way, I can fix the acidity problem without making the pH problem worse. We know that acids can make a wine taste tart, but there are other influences on a wine’s taste. Tannins provide bitterness, while sugar and alcohol provide sweetness. A wine tastes best when none of these influences overpower the others. Such a wine is said to be in balance. You can actually think of it as an old fashioned balance scale, with tannin (bitterness) and acid (sourness) on one side. Sugar and alcohol, both providing sweetness, would be on the other. My cherry wine is out of balance, with too much acidity. Since I don’t want to make a fortified wine, my best bet for bringing the wine back into balance is to add sugar. To do this, I need to wait until the yeast is dormant. Then I can stabilize the wine with sorbate, which prevents the yeast from fermenting the added sugar, and sweeten.

But I have to wait until the yeast goes dormant

To determine if the yeast is dormant, I looked at the specific gravity. It was 1.007, which indicates some residual sugar. Either the fermentation had stuck or the yeast is still (slowly) fermenting. I can’t say for certain, so I’ll rack the wine now, which will get it off the sediment, and recheck in a few months. If the SG hasn’t changed, then I’ll know the yeast is inactive. If, on the other hand, the yeast was still going, it will likely finish at a lower SG in those months. Either way, I anticipate stabilizing and sweetening then. Waiting a few months will also let me repeat the TA and pH measurements. A high pH and a high TA is out of the ordinary, so I’d like to double check. Right now, I’ve got some racking to do.

Update 2/23/2009: More options for high pH – high TA wines

I’ve run into the same problem again, and I’ve given it some more thought. Sweetening to bring the wine into balance solves half of the problem, without making the other half worse, and that’s an improvement. I may have found a way to solve both halves of the problem by using phosphoric acid. I talk about that in a new post about solving acidity problems.

Update 5/25/2009: A happy ending

It’s in the bottle and worth the effort – an enjoyable red wine and I would recommend it to anyone interested in this approach.

Oregano Wine Recipe: pH restored

I’ve been stirring my oregano wine every day since I used potassium bicarbonate to raise the pH. Yesterday I took some measurements, and I found some good news and some bad news. The good news is that I succeeded in raising the pH to 3.67, and that’s high enough to permit fermentation. The bad news is that it hasn’t actually started fermenting again. It’s a waiting game for now, but if I don’t see activity in the next few days I’ll add more yeast.

Oregano Wine Recipe: restarting a stuck fermentation

I tested a sample of my oregano wine yesterday. The specific gravity is 1.053 and the pH is 2.62. These results are virtually unchanged from 7/13/07 when I first noticed the pH crash that stopped the yeast in their tracks. I’ll try to get them going again by neutralizing some of the acid, raising the pH, with potassium bicarbonate (KHCO3). I had planned on adding two teaspoons because I wanted to add about 10 grams, and I believed that one teaspoon was 4.8 grams. The vendor, Crosby & Baker, says that 1 teaspoon is about 6 grams and warns against using more than 10-13 grams per gallon. That would put two teaspoons, at about 12 grams, very close to the upper limit, and since measuring spoons are not precise I decided to only add one teaspoon this time. I’ll see if fermentation restarts and I’ll retest the pH.

I’ve also decided to add one teaspoon of cream of tartar. The reaction of KHCO3 with tartaric acid will create cream of tartar. By adding some more, I’m seeding the wine and that will encourage the newly created stuff to precipitate out more easily. I’m also hoping it will improve the buffering capacity of the wine.

Oregano Wine Recipe: fixing the pH crash

I’ve been thinking about the pH drop that brought fermentation to a near halt, and I’ve decided to deacidify with potassium bicarbonate (KHCO3). Most of the information I could find on neutralizing acid has to do with reducing the total acidity (TA); I couldn’t find anything about deliberately raising the pH. That means I have no clear guide in deciding how much KHCO3 to add. When I last measured the TA, it was 6 g/L. I’ve arbitrarily decided to neutralize half of it. To reduce the acidity by 1 g/L, you need to add 0.9 g/L of KHCO3. Since I’ve got a gallon (3.785 L) of wine and I want to neutralize 3 g/L of acidity, I need to add 10.2 g KHCO3 (0.9 * 3.785 * 3). I haven’t got a scale accurate enough to measure out 10.2 grams of anything, but a teaspoon of KHCO3 is about 4.8 g so adding two teaspoons (about 9.6 g) gets me pretty darn close to 10.2 g.

So what happens when I add the KHCO3? It combines with the tartaric acid to form potassium bitartrate (cream of tartar), carbon dioxide, and water. The cream of tartar precipitates out and the CO2 bubbles off leaving a tiny bit of water. That should leave the wine with a high enough pH to kick start the fermentation. I’ve ordered the KHCO3, it will arrive in a few days, and then we’ll see if there’s method to my madness.

Most of the info on neutralizing acid came from Philip Jackisch’s Modern Winemaking. It’s a good book that provides technical detail on winemaking processes with examples. It’s for the winemaker looking to go beyond the basics, and I highly recommend it. There’s even has a chapter on non-grape wines!

Oregano Wine Recipe: pH crash

pH meter, in champaign glass about one quarter full of oregano wine, shows a pH of 2.69.My oregano wine has been fermenting very slowly, and I suspected a pH problem. I was following a recipe that called for 3 tsp of acid blend. I decided to add only 1 tsp at the beginning, because I was afraid the pH could drop so low that it would inhibit the yeast. The must was mainly sugar and water, so there wasn’t much to buffer it – a little acid could push the pH a long way. Yeast has a difficult time when the pH drops below 3. I decided to take a sample and do some measurements. The pH meter, reading 2.69, confirmed my suspicion. The specific gravity was 1.052, which is less than the 1.060 on 6/30/07. That means it’s still fermenting, but it’s been over a month and it’s still got a long way to go. I measured the TA as 6 g/L (tartaric). I’m not sure what to do about this yet. I might be able to rack it and let it ferment out slowly under an airlock. I could try and neutralize some of the acid, pushing up the pH, to get fermentation going again.

Update 7/25/2007 – Fixing the pH crash by neutralizing acid

To fix the pH crash, I neutralized some of the acid with potassium bicarbonate (KHCO3). This will raise the pH and should get things going again

I Bought A pH Meter

I’ve used pH papers for a while, but in making red wine from cherries I’ve gone beyond their limits. I can’t read the color very well when I’m measuring dark colored wine, and for the same reason, its tough to do acid titration with an indicator. Since I didn’t have a good way to measure it, I didn’t adjust the acidity of my cherry wine. Well it’s been fermenting away, but I didn’t solve that problem I just bought a little time. During that time, I ordered a cheap pH meter and I expect it to arrive today.

There’s an old saying that if you buy cheap, you buy twice. That probably applies here, but sometimes that’s not a bad thing. Buying cheap can be a good way to learn just what you need in a tool, and help you buy intelligently later on. I understand that replacement tips for high end pH meters cost about what my meter cost, so it might be smart to just buy a new cheap meter every time the old one breaks. I don’t know yet, but right now I can measure acidity a lot more accurately than in the past. That should mean better wine, and I’m excited about that!

White Wine From Tomatoes!

Different for a reason: Why I’ll make it white

When most people think about tomato wine, they – ok, most people don’t think about tomato wine, but if they did they would – think about red wine. It’s the same way with cherry wine, and just as I wrote about white cherry wine a few days ago, I’m going to make the case for white tomato wine today.

Since I’ve neither made nor tasted tomato wine before, I’m a little concerned about the taste. If there are objectionable flavors, then I think they’re most likely to come from the skin and pulp. A white wine is just fermented juice, so that would avoid the flavor compounds, good or bad, in the skins. As for the pulp, I’d want to stay away from sauce tomatoes, like Romas. In the end, I chose to make a clean dry white from Gold Nugget tomatoes. Gold Nugget is a cherry tomato with yellow/orange skin and yellow flesh that’s a reliable producer in this climate.

How to make it: Good fruit, balanced acid, and the right amount of alcohol

I have ten vines in the ground, and I don’t know how big a harvest to expect. I’ll pick each tomato when it’s ripe and put the day’s harvest right into the freezer. It won’t come in all at once, though, so I’ll store the fruit until the harvest is complete. That’s not the only thing about tomatoes that’s different from grapes. Tomatoes are about 95% water, by weight, compared to 80% for grapes.

The dominant acid in tomatoes is citric, rather than tartaric. I haven’t been able to find information on the acidity of tomato juice, but if the TA is low, then I’ll have to add acid to the must. In that case, I can choose one, or a combination, of the three major organic acids found in most fruit: citric, malic, and tartaric. Winemakers always use tartaric acid for any additions to conventional grape wine, but there are two schools of thought for acid additions to non-grape wine. The first approach is to use the dominant acid in the fruit. In the case of tomato wine, that would be citric. Another idea is to use a complementary acid. That is, instead of the dominant acid, add one of the other two. So I could use either malic or tartaric with this method. Should I need to acidify, I’ll probably use tartaric. I think it’ll make the a wine a little more familiar by giving it a bit of conventional white wine character. Also, I understand that citric acid can make the wine more vulnerable to vinegar spoilage and that malic can be harsher than the other two.

There will be a lot less sugar in the tomato juice, than in grape juice. I understand 5-8 degrees brix is common, so I’ll be adding sugar. It’s pretty straightforward to find out how much sugar to add for a given amount of alcohol. The question is, how much alcohol should I target? I often aim for 12% alcohol, by volume, in my wines and meads. That would be about 22 brix and a specific gravity of 1.090. Some research, by the late Dr Kime of Cornell, suggests that fruit wine (I’ve never liked that term – grapes aren’t fruit?) is better below 10.5% alcohol. There isn’t a whole lot of research into non-grape wine, so when a little bit come along, I pay attention. I’m leaning towards 10% alcohol for my tomato wine (18-19 brix, SG = 1.075). I’ve still got some blanks to fill in, but I’m getting a pretty good “big picture” idea of how I’ll make my white tomato wine.

Thinking about the next step

If this is a success, then I can continue investigating tomato wine. I don’t want to get ahead of myself, but I can see a red tomato wine next year. Red wine is all about the skins, and smaller fruit has more skin, pound for pound, than larger fruit. That’s why wine grapes are a lot smaller than the table grapes in the grocery store. So I would need cherry or grape tomatoes, for red wine, with deep dark color. I wonder if there are any dark colored small tomatoes that do well in this climate? I don’t know, but if my white tomato wine is a winner, then I’ve got plenty more to think about!

Update 12/22/2007: I finally did it!

The acidity of tomato juice is low, and I added tartaric acid just as I planned. I changed my mind about targeting a low alcohol level, and decided that my first tomato wine should be a more “normal” 12% alcohol. You can read all the details here.

White Wine From Cherries?

Isn’t cherry wine is supposed to be red?

I mentioned white cherry wine in passing here, but most people think of cherry wine as a red. The only commercial cherry wine I’ve tried is a red – crushed, fermented on the skins, then pressed. Every recipe I’ve seen involves either fermenting on the skins or fermenting red juice. When I first made cherry wine, last year, I wanted to make it like a conventional grape wine rather than a “country wine” (4-6 lb of fruit per gallon, with added water, sugar, and acid). I made a red cherry wine. In fact, it never occurred to me that I might make a white.

So why a white cherry wine?

There’s a story about white Zinfandel, and how difficult it was to get it accepted. Reviewers reviewed harshly and judges judged skeptically because everyone knew than Zinfandel was supposed to be red. Eventually this new white was judged on it merits and has become a popular wine. Now, I’m not sure if this story is actually true (anyone out there know?), and I don’t even drink white Zin, but why not a white cherry?

How do you make white cherry wine?

Two of the cherry trees I grow, Montmorency and White Gold, will produce fruit with clear juice. I was looking for that specifically, because I wanted to make white wine from them. The idea is to keep the process as close as possible to a conventional white wine from grapes. Crush and press the fruit, adjust the sugar and acidity of the juice, then pitch the yeast. I’m open to diluting with water if the acidity is too high, but I’m hoping that won’t be necessary. I’m also willing to be flexible about what “too high” is. If the acid profile looks like Riesling, I may just treat it like one rather than “correct” it to more normal levels. If I get enough fruit from each tree, I’d like to ferment them separately. That way I can see how each tastes on its own, then try different blends. Plenty of ideas, not enough cherries!