Category Archives: winemaking

Pumpkin Wine: Trick or Treat?

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Being a kid on Halloween meant dressing up in a costume, staying out after dark, and asking strangers for candy. Saying it like that makes it sound kinda strange – maybe even dangerous – why on earth would I do something like that? I was a young boy, so I did most things because they were strange and dangerous. Ah the good ole days! So, can a sensible but bored adult still live on the edge a little on Halloween? I don’t know, but it made me think about pumpkin wine.

Starch makes pumpkin different from other wine bases

Pumpkins contain starch, which is a lot (hundreds or thousands) of sugar molecules stuck together. These molecules fit together in a tight compact mass, making raw pumpkin flesh hard and unpalatable. In order to make wine from it, we need to extract the flavor and aroma compounds with water. To do that, we need to loosen up that tight compact mass and allow the water to penetrate. That means cooking. There are several ways to do this. One way is to cut the pumpkin in half, remove the seeds and pulp, then bake the two halves, flesh sides down, in a cookie sheet at 350F for 30 minutes.

Mashing the pumpkin

Winemakers and homebrewers treat starch very differently. For winemakers, starch is a problem that causes haze. Homebrewers convert starch to fermentable sugar by “mashing” it, and when they’re using pumpkin in their brews, they’ll often bake it and toss it in the mash. We can borrow that technique from our homebrewing friends and mash the pumpkin flesh. We’ll need to add enzymes that will break down the starch, and we’ll need to control the temperature so that it’s warm enough for the enzymes to do their work, but not so hot that they are destroyed. It turns out that there are two important enzymes that work together on this, but each works best at a slightly different temperature. A compromise that works well is to hold the mash at 150F (about 66C) for 30 minutes.

You can make pumpkin wine without mashing, but there are two benefits that make it worthwhile. By converting the starch, you increase the amount of fermentable sugar and ensure that no starch ends up in your wine. The extra sugar probably isn’t all that significant, but starch in your wine can cause a haze and support spoilage organisms. Those are headaches worth avoiding.

Towards a pumpkin wine recipe

A recipe or procedure for making pumpkin wine is still a work in progress for me. The starch in pumpkin makes it so different from other sorts of wines that I wanted to address it separately. This pumpkin wine looks a lot like a beer so far, and you can make good pumpkin beers, but next time I’ll address sugar, acidity, and the typical issues in making a wine.



Hot Pressing In A Cool Climate

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Great news for fungi, bad news for grapes

The cool climate, here in the Puget Sound Region, keeps growers on the edge. We want to grow noble varieties like Pinot Noir and Chardonnay, which will ripen here but just barely. We also want reliable grapes that ripen even in bad years like this one. Grapes like Madeleine Angevine and Seigerrebe shrugged off the cold wet season and delivered good, if somewhat smaller, crops. A lot of Pinot Noir and Chardonnay is still braving the wet weather, and the fungal diseases that thrive in it, to ripen. Some wont be harvested at all, and many will be harvested with the beginnings of botrytis.

Heat the grapes to repair some of the damage

How do you salvage barley ripe grapes beset by bunch rot? Thermovinification, or “hot pressing,” is the process of heating red wine grapes to kill spoilage organisms, improve color, and reduce unripe flavors. Heating to 150F (65C) for 20 minutes, 180F (90C) for 2 minutes, will do the trick. At this point you can cool the must and ferment normally or press the grapes and ferment like a white wine. It’s best not to leave under ripe grape skins in contact with the fermenting wine for very long.

Adjust the acidity

If you had to harvest before your grapes are ripe, you will have to deal with their acid profile. It isn’t just a matter of reducing high acid levels with something like potassium bicarbonate (KHCO3), the mix of acids may be unfavorable. As grapes ripen, the amount of malic acid falls, while tartaric acid rises. So in under ripe grapes, there will be a disproportionately more malic. That’s when a yeast like Lavlin’s 71B, which consumes malic acid, can come in handy. If, after fermentation, there is still too much acid, then it’s time for the KHCO3.

These steps can make the difference between a lost cause and a drinkable wine, but they won’t conjure up a fine wine from mediocre grapes. Do your best, look forward to next year, and sip some heat treated wine 🙂

Further reading

In his 10/3/2003 Letter to NY winemakers, Thomas Henick-Kling writes about making wine after a difficult harvest. My thanks to Gerard Bentryn of Bainbridge Island Vineyards for recommending that paper.

Jancis Robinson has a great entry on thermovinification in her The Oxford Companion to Wine.



Raspberry Wine Recipe

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I made raspberry wine last year. I haven’t talked about it before because I made it and racked it before I started blogging. I also made it before I owned a pH meter or an acid test kit, so I was really flying blind. How do you make raspberry wine without measuring the acidity? I measured what I could, then I consulted Ben Rotter’s table of fruit data. It’s a goldmine of data about sugar, acid, and tannins in fruit as well as juice yield.

Raspberry Wine Recipe

My 10.75 lb (4.9 kg) of raspberries yielded 3 quarts (2.8 liters) of SG 1.050 juice. My notes show that I expected a TA of 14-18 g/L, though when I look at the table now that seems low. I picked the fruit at a U-pick farm after some unusually hot weather. My notes don’t say, but maybe I was expecting the hot weather to lower the acid. At any rate, I dissolved 3 lb (1.4 kg) sugar in 3.3 quarts (3.1 liters) of water. I treated with sulfite, pectic enzyme, and nutrient then pitched the yeast. It fermented to dryness in less than two weeks.

More on raspberry wine

Promising, but too acidic

I did some measurements recently:

SG = 0.992
TA = 14 g/L
pH = 2.96
volume = 1.5 gallons (5.7 liters)

It tasted tart, but it wasn’t the undrinkable firewater you might expect. There was a very nice flavor in there, and it complemented the raspberry aroma very well. I decided to use potassium bicarbonate (KHCO3), to take down the acid a notch, at a 1.5 tsp/Gallon (2.4 g/L) rate. I’m hoping to reduce the acid by 2-3 g/L. I’ve set it aside, with the cherry wine, and intend to taste them both in a few months. Maybe that’s all the raspberry wine needs, or maybe the acidity will still be too much. If so, it’ll be time to sweeten it a little.

Do as I say, not as I do!

I think this is going to have a happy ending, but you really should do your own measurements. Bookmark Ben’s site, and not just for the fruit data, and use it to help make your own recipes, but make final decisions about acid and fruit proportions based on accurate measurements of the fruit you are using.

Update 12/9/2008 – It needed sweetening

It’s still too tart, even after neutralizing some of the acid, so I sweetened my raspberry wine.

Why I Make Dry Wine

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I make wine out of many different fruits and vegetables – from raspberries to rhubarb and all sorts of things in between. That makes for a lot of trial and error as I learn how to consistently make a good wine using very different bases. Many traditional country wine recipes call for a small amount of fruit, a lot of water, enough sugar for 12% alcohol, and acid to balance. You can make (and I have made) good wine this way, and it’s a real money saver. Still, adding a lot of water bothers me and some of the wines I’ve made this way seemed to suffer for it.

That made me wonder what would happen if I used more fruit. What about all fruit and no water? I’m trying this with cherry wine right now, and the first problem I had was in managing the acids. The titratable acidity (TA) of my cherry wine will be high, and that’s something I’ll need to address the next time I make it. I’m working on some ideas, but in the meantime I’ve decided to sweeten the cherry wine. I’ll be trying to balance the acid with sugar and make a drinkable wine out of it.

Learning to make good sweet wine by making good dry wine

I wrote about how to rescue bad wine with sugar on Monday, and the reason this works is also the reason I usually make my wines dry. That might seem strange; if sugar can save bad wines, why can’t it improve any wine? Used correctly, it probably can. Sweet things taste good to all of us, that’s just human physiology. But sugar can mask faults in a wine, and that’s why I stay away from it while I’m learning and experimenting. I need to be able to see the problems in order to fix them. When I understand what I’m doing with a particular wine well enough to make a good one consistently, then I’ll think about making a sweet or off-dry wine.

Primary Fermenters: What size do you need?

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I’m excited about making red wine from grapes this year. It will be my first red, and I needed some new equipment. My largest fermenter has a ten gallon capacity, which is enough for five or six gallons of white wine, but too small for five gallons of red wine. Red wine is fermented on the skins, so you have a larger volume of must than for the same amount of white wine. All that skin and pulp gets forced to the surface, by CO2, forming a “cap.” So the fermenter has to be bigger than the amount of finished wine, to handle the skin and pulp and to contain the cap. How much bigger? A good rule of thumb is that every 5 lb of grapes require 1 gallon of capacity (0.6 kg/liter). For 100 lb (45.5 kg) of grapes, then, I’ll need a 20 gallon (75 liter) fermenter. My local homebrew shop carries 24 gallon (90 liter) fermenters. It’s ok to have a little more room than you need, but it’s a little messy if you’re short so I bought one. All I need now are some grapes!

Buying Grapes To Make Wine

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White wines are easy but some reds are worth it

I ordered wine grapes yesterday – 100 lb (about 45.5 kg) of Chardonnay and 100 lb of Merlot. That should yield about 5 gallons (19 liters), each, of finished wine. This will be the third time I’ve ordered wine grapes from my local homebrew shop, but the first time I’ve ordered red wine grapes from them. That’s because I’m relying on them to crush and press for me. Since I’ll be pressing the red grapes after they’ve fermented for a few days, I’ll have to load up the fermenter, all 100 lb of it, and haul it back to the homebrew shop to have it pressed. This two step process makes red wine more of a hassle than white, but this year I decided that the high-maintenance red was worth it.

Merlot: Red wine with a home state connection

There were several other choices of red wine grapes, like Cabernet Sauvignon, Cabernet Franc, Lemberger, and Syrah. I chose Merlot because it’s become associated with Washington state in a way the others haven’t. Just as Oregon is becoming known for it’s Pinot Noir, Washington is making a name for itself with Merlot. What other grape would a Washington Winemaker choose for his first red?

Chardonnay: A white wine grape that grows in the Puget Sound AVA

As much as I’ve been taken in by the promise and allure of a good Merlot this year, I couldn’t bring myself to halt my affair with white wines. They’re easier, cheaper, and terrific when young. Don’t be fooled, though, a well made white can age gracefully into a sophisticated and elegant wine. I could have chosen many different white wine grapes too. I passed up Semillon, Sauvignon Blanc, Chenin Blanc, and Gewürztraminer for Chardonnay. I’ve made Sauvignon Blanc twice before and loved it, and I’m curious about blending it with Semillon. Gewürztraminer is a parent of Siegerrebe, which I grow in my bonsai vineyard, so I’d like to try that one day. I chose Chardonnay because it is grown commercially in the Puget Sound region, and I intend to grow it myself.

Merlot, and Chardonnay – the choices are made and the grapes have been ordered. Now all I have to do is wait.

Restarting a stuck fermentation

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Don’t panic!

It happens. Sometimes, after a promising start full of froth and vigor, the yeast tap out and leave a partially fermented must/wine. It’s not drinkable and you certainly shouldn’t bottle it, but it’s also vulnerable to spoilage. So how do you get the yeast going again? I’ll explain how I do it, and use my oregano wine as an example.

Find out, and correct, the problem

It’s not always apparent what went wrong, but it’s worth the effort to try and find out. If there is some underlying problem that is inhibiting the yeast, then just adding more yeast, even a vigorous starter, won’t help. This is where good measurements and careful note-taking pay off. Nobody ever plans for things to go wrong, and that’s why good habits should become habits. My oregano wine suffered from a pH problem, and that brought fermentation to a halt. I suspected the pH after reviewing my notes, and confirmed it with a measurement.

Other potential problems that you might consider are temperature, preservative in store bought juice, nutrient deficiency, or lack of oxygen. Review your notes, take measurements, and do your best to discover why your yeast stuck.

The yeast began fermenting again, albeit very slowly, after I corrected the problem. It probably would have fermented out, eventually, if I had left it alone. A long slow fermentation like that is risky, however, so I decided to treat it as though it were stuck and hurry things up a bit.

Gradually add the stuck wine to a vigorous starter

After fixing the underlying problem, you should make a starter. This builds up a large population of actively growing yeast. Add some of the stuck wine to the starter. I like to double the volume every four hours or so, and since my starter was about a cup, I added a cup of wine to it. Four hours later: two more cups. Four hours after that would have been well into the wee hours, so with about a quart (close to a liter) of fermenting wine, I went to bed. In the morning I added another quart.

Nutrient: Not too much, not too little

Without enough nutrient, the new yeast may have trouble growing and fermenting the wine. If there’s more than the yeast can consume, some nutrient will remain in the fermented wine. That can cause off flavors all by itself, and it can also support spoilage organisms. So there’s no way I can tell you how much, if any, nutrient to add at this stage. The best way to decide is to measure the available nitrogen in the must, but it’s pretty unusual for home wine makers to run such an involved test.

If you haven’t got a chemist and a state of the art lab handy, gather up all the information you have about how much nutrient was in the must, how much you added, and how much yeast activity there was. Did I mention the part about good notes? If you started with a lot of nutrient and the yeast didn’t get very far, then you shouldn’t add much (or any) nutrient. If, for whatever reason, you’re starting nutrient level was low then you should add some. I realize that “a lot”, “much”, “low”, and “some” are a little vague, but the only way to get precise answers is with that chemist and the state of the art lab that we haven’t got.

My Oregano Wine recipe called for 1 tsp/Gallon of diammonium phosphate, which isn’t a lot. Since the must was basically a sugared oregano tea, it had virtually no nutrient except for what I added. So I decided to add another tsp of DAP along with the yeast starter.

I’d like to say that you won’t have to deal with stuck fermentations, but if you make wine regularly you’ll probably have to face an unmoving hydrometer sooner or later. Your best bet is to start dealing with it before it happens with good procedures and meticulous note taking. If you do that and use your head, you’ll have a good shot at saving your wine.

Oregano Wine Recipe: First racking – at last!

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Oregano Wine after racking on 9/3/07


I’ve never been happier with a specific gravity measurement than this one: 0.993 on 8/31/07. After the pH crash and the stuck fermentation, after the potassium bicarbonate addition and the yeast starter, and after all that waiting my Oregano Wine has finally fermented out! I racked on 9/3/07 to a 1-gallon jug and a half-bottle. I poured the thick slurry that was left into a beer bottle to settle. I’m a little worried about oxidation because I’ve kept the wine in it’s primary fermenter since June, but there is no sign yet and I’ve treated with sulfite.

Produce Department Chablis – First racking

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Produce Department Chablis after racking on 9/3/07


I measured the specific gravity on 8/31/07, and at 0.991 it had fermented out and was ready to rack. So yesterday I siphoned the young wine into a 1-gallon jug and a beer bottle. There was some thick slurry left in the fermenter, and I poured that into another beer bottle to settle. I should be able to recover some clear wine from that, and every little bit helps! I’ll let the wine sit for a while. It will clear and the yeast will settle to the bottom. Then I’ll measure the pH and titratable acidity, make adjustments if necessary, and rack again. In the meantime, I’ll have to think about changing the name to “Produce Department Rose” – how about that color!

Produce Department Chablis

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Welch’s wine? While you’re at the grocery store, head over to the freezer section for some frozen grape juice concentrate. Then try my Welch’s wine recipe and see how it compares.I’ve always wanted to make wine from grocery store grapes. It’s not that I’m expecting greatness, but that I’m really curious. Grapes were on sale for $0.88/lb. One variety was Thomson Seedless, the others were just called “red” and “black”. They were all seedless, and they all tasted the same to me. I ended up buying roughly equal amounts of all three, 20.34 lb total, to make wine with. Here’s how I did it:

Ingredients

About 20 lb (9.2 kg) of seedless table grapes
1 tsp pectic enzyme (approximately 2.3 g)
sulfite to 50 ppm (equivalent to 1.5 campden tablets)
sugar to SG 1.090 (about 0.375 lb or 170 grams in my case)
Premier Cuvee yeast

Sort and destem, then extract the juice

After discarding the moldy ones and destemming the rest by hand, I had 19.4 lb (8.835 kg) of grapes.

Red, green, and black seedless grapes half-filling their own 2-gallon buckets

There’s more than one way to juice grapes. I’ve used grape crushers and bladder presses when I bought wine grapes. I’ve crushed cherries with my feet when I made cherry wine. I’ve even built a simple press out of three plastic buckets. This time I ran my grapes through a juicer that I’ve been meaning to try.

Juicing the grapes with a Juiceman 210

It worked pretty well, though I did have to stop and clean the filter screen a few times. I ended up with about 5.44 quarts (5.15 liters) of juice which works out to one gallon from 14.25 lb of fruit (one liter from 1.7 kg). That is almost exactly what I got from Riesling grapes when I used a crusher and bladder press (one gallon from 14.29 lb of fruit).

Measure the sugar and acid

Up to this point, I kept each batch of grapes and their juice, separate. I was curious if I’d notice a difference in flavor or yield. I also wondered how much color the red and black juice would have. Well the yield was nearly identical and they tasted the same to me, but the red and black grapes did yield colored juice. This may end up as a blush or rose if that color persists in the finished wine. It would have been a little tedious to ferment them as three separate batches, so I combined them and added the sulfite and pectic enzyme. Next, I needed to measure the sugar and acidity, to know what adjustments to make.

Red, green, and black grape juice each half filling a 1-gallon jug

It was easy enough to draw a sample and measure the acidity. The pH was 3.35 and the TA was 7 g/L, as tartaric. Dry white wine musts are normally 7 – 9 g/L TA and 3.1 – 3.4 pH, so no need to adjust the acidity.

The suspended solids in the juice were going to make it difficult to measure the sugar. To get an idea of how much sugar there is, I measure the specific gravity with a hydrometer. Suspended solids in the juice will raise the SG, making it look like the sugar content is higher than it really is. So I decided to let the must sit overnight. This would let the pectic enzyme do it’s work and allow many of the solids to settle out. With luck, I could get a clear sample and get a meaningful SG reading.

I always worry about my must when I have to let it sit for any length of time. Yes, the sulfite will protect it, but I’d feel better if the yeast were busy. Having them dominate a must, and ferment to dryness quickly, is a great defense against spoilage organisms. So I decided to make a starter. I didn’t follow my own careful instructions, here, rather I just added the rehydrated yeast to 0.5 cups (120 ml) of must and let it go overnight.

Measure and adjust the sugar

By morning, the starter was happily bubbling and I checked in on the must. It’s not as though all the solids dropped to the bottom and I had a gallon of crystal clear juice to sample, but with some care I was able to coax 0.5 cups of clear pink juice into my test jar. The SG was about 1.078, and I’m aiming for 1.090. So I need to add sugar. How much? The short answer is that 0.375 lb (170 grams) of sugar dissolved in just under 0.5 cups (100 ml) of water (boil and cool the sugar water to keep out the nasties) will bring the SG up to 1.090. You can use this formula to calculate how much sugar water (2 parts sugar, by volume, and 1 part water) to add to your own must:

x = ( V * (TG – SG) ) / (1.310 – TG)

where x is the amount of sugar water, in liters, to add
V is the volume of must, in liters (5.15, in my case)
TG is your specific gravity target (1.090)
SG is the current specific gravity of your must (1.078)

If you’re wondering where the 1.310 came from, it’s the specific gravity of sugar water. So make sure you use 2 parts sugar (by volume) to 1 part water or the above formula won’t work. In my case x was equal to 0.281 liters. To make the math and the measurements easier, I rounded that to 300 ml. That means I needed 200 ml of sugar, which weighs about 170 g, dissolved in 100 ml of water.

I added the sugar, pitched the starter, and noticed vigorous fermentation in hours. Wine from produce-section grapes! Who knows how it will taste, but pretty cool, huh?

Update 7/27/2009 – Sugar additions the easy way!

If you’re put off by the math I used to adjust the sugar, check out my new Wine Recipe Wizard. I wanted to make sugar and acid adjustments easier by just having you type in the volume of juice you have, your hydrometer reading, and (optionally) your titratable acidity. Then just type in what you want the sugar and acid to be and the wizard will tell you what to add. I hope this helps – let me know if you have trouble using it.

Update 11/15/2009 – Disappointing

I don’t think I ever had high expectations for this wine. I never imagined comparing it to an aged Premier Cru Chablis, but I was hoping for a nice table wine. I didn’t get that. The wine is balanced, there are no faults, but there is no flavor either. I’m starting to think about how to improve the procedure, but until that stroke of genius hits, I had to say that wine from grocery store grapes is bland.

Update 12/3/2009 – Save it by making mulled wine?

When produce department grapes give you something bland, make mulled wine! I’m hoping that traditional mulling spices like cinnamon and clove along with citrus zest will add some life to this wine. This will be my first time making mulled wine, so I’m excited!