August 4, 2017

Making Blueberry Jam, Using Ume/梅を使って、ブルーベリージャムを作る

On August 2, my father got more than 2 kg of frozen blueberries from a neighbor.
I was given the assignment of turning them into jam. I first thought it was an easy task.
I first put the 2 kg of blueberries in two Tupperware containers, microwaved each container with 300 g of sugar in a 600-W microwave oven for a total of 4 x 3 = 12 minutes.
まず2キロのブルーベリーを2つのタッパー容器に入れ、各容器に砂糖を300 g入れて600Wの電子レンジで合計4 x 3 = 12分加熱しました。
Very watery. I left them overnight to see how the texture would change.
On the early morning of August 3, I checked them and found they were still watery. My father tasted some, and didn't like it. I decided to simmer them in an enameled pot for 20-30 minutes.

I added 400 g of sugar to the pot to make the blueberry to sugar ratio 2 to 1. I simmered them for 30 minutes. Still quite watery.
鍋に砂糖を400 g入れて、ブルーベリーと砂糖の割合を2:1にし、30分煮ました。まだかなり水っぽいです。
I decided to add two of the eight ripe ume that had been sitting in the freezer to add pectin.

After simmering for several minutes, I checked to see if the added ume had changed the flavor of the contents of the pot. I found that the ume had enhanced the flavor. The texture was still watery, however.

I later added two more.
Still watery. I decided to add all the remaining four ume.
I also added 200 g of sugar so that the jam would contain 60% sugar.
また、ジャム砂糖含有量が6割になるよう、砂糖を200 g足しました。

Still not quite jam-like texture. I decided to leave it overnight.

This early morning, I checked the texture to find it was slightly thicker than last night.

This time, I got an OK from my father. I rinsed four empty blueberry jam glass bottles with running water, and microwaved them, two at a time, in a 600-W microwave oven for one and a half minutes in an attempt to sterilize them.
My father consumes a considerable amount of store-bought blueberry jam with yogurt every morning. Luckily, I have saved some of the empty bottles.
The jam made from 2 kg of blueberries and 1.2 kg of sugar filled the four glass bottles.

I told my father that these four bottles contained eight ume seeds and that he should be careful when consuming the jam.

Why did I add ume, you might ask. Lemon juice is usually added as a source of pectin, but I didn't want to drive just to get some lemon juice. Ume contain a considerable amount of pectin, and besides, I know from the home-made grape jelly that ume have a potential to enhance the flavor of another type of fruit.


Khash said...


I just wanted to say that I love how you do not constrain yourself to just following a reciepe blindly.
It is very clear that you actually understand food and what you are doing and you're not afraid of a little experimentation.
Great stuff here, I keep learning.

Separately, is Ume a type of plum?

Hiroyuki said...

Khash: Thank you for your compliment!

Ume is usually called a Japanese plum, but it's actually more closely related to the apricot. BUT, you will realize that it's totally different from the apricot as soon as you take a bite at one ume!

Khash said...

Aah, okay, thanks.

I don't think we can get the actual fruit here. Do you think something like this has the flavour (of course not using pickle for jams)

ErinBear said...

Hello Hiroyuki,

I'm glad you found a solution to thicken the jam! Here, when people are cooking with blueberries, we sometimes use an apple for pectin. The apple has a mild flavor, so you can still taste the blueberries, and they have a lot of pectin. If this problem comes up again, that might be another fruit you can use. Thank you for your blog!

Take care,
Erin in California

Hiroyuki said...

Khash: The particular crunchy ume product linked to is pickled but not dried. This and umeboshi (salted and dried ume) do not taste like ume. If you want to know the flavor of ume, I would suggest searching for umeshu (ume liqueur) or ume jam.

ErinBear: Thank you for your suggestion!

I had no idea why the blueberries remained watery. Maybe they were not fully drained before frozen. Anyway, my father said the resultant jam was much better than the store-bought.

ErinBear said...

Hiroyuki, sometimes when you are making jam or pie, it is better if the fruit is a little less ripe. Maybe the blueberries were very ripe, and that is why they were more watery in the jam. When you eat them fresh, they taste delicious when they are very ripe. But for pie or jam, it is not as good. Like you noticed, it is because of the pectin, and they do not get as thick when they cook. Still, it tastes very good. When jam is runny, you can also use it as a sauce on things, like plain yogurt, ice cream, or cake. It is still wonderful!

Take care,
Erin in California

Hiroyuki said...

ErinBear: Thanks again! I guess those blueberries were quite ripe. When I tasted them, they were very sweet.

The home-made jam is still rather runny, but that's ideal for my father's use: Adding lots and lots of it to plain yogurt!

Nerd Mom said...

Your blueberry post reminds me of a yummy treat I had this spring. There is a shop in San Francisco that sells freshly made daifuku and other related products. They offer daifuku with fresh fruit inside, and the last time I stopped there they had blueberry ones. It's really delicious.

Generally speaking, frozen fruit is going to be more watery... maybe next time simmer it for longer to remove the excess moisture.

Hiroyuki said...

Nerd Mom: Have ichigo (strawberry) and other types of daifuku made their way into the United States?! How interesting!

Well, simmering while constantly stiring with a wooden spatula is so boring that I may separate the liquid from the blueberries after thawing...

Yangsze said...

What a great idea to use ume! If your jam is watery, adding some chopped apple while simmering it will also help it set, since apples contain a lot of pectin. The blueberry jam looks delicious :)

Hiroyuki said...

Yangsze: Thank you for your suggestion. The next time I blueberry jam, I will use lemon juice, chopped apple, or ume depending on the availability!

Khash said...

I'm pretty sure I can find Umeshu here. Ume and alcohol, win win!!

Thanks Hiroyuki-san

Nerd Mom said...

I live in California, and most of the larger cities (San Francisco, San Jose, Los Angeles, Sacramento, San Diego) have at least one shop selling handcrafted wagashi. A few of the shops, like Benkyodo in San Francisco and Fugetsu Do in Los Angeles have been in business for over 100 years. The blueberry daifuku I mentioned was purchased at Benkyodo. I'm told their fresh fruit daifuku is quite popular and sells out fast, and it's not just Japanese-American people buying it either.

Right now, mochi ice cream (yukimi daifuku) is very popular in the United States. It's made it to places where people don't know what traditional mochi is like. Depending on which company makes it and how it's stored, it can be good or it can be awful.

Back to the jam making, most of the blueberry jam recipes I'm familiar with call for thawing and draining the frozen berries first and to add additional pectin, so that might explain why your jam was watery. Ume is a high pectin fruit, so if you add ume next time AND drain the frozen berries, your jam should be thicker.

Hiroyuki said...

Nerd Mom: Thanks for the info. I have just checked the websites of these two shops. I'm amused to learn that both shops carry peanut butter mochi, maybe an Americanized version of mochi?

Nerd Mom said...

The peanut butter mochi and the chocolate mochi are definitely American influenced. I'm not a fan of the peanut butter mochi though. Hawaiians have also done interesting things with mochi. Butter mochi is delicious, but only slightly resembles the mochi I grew up with.

Hiroyuki said...

Nerd Mom: I have checked one butter mochi recipe on the Internet. Baking powder, evaporated milk, and coconut milk! The texture should be quite different from regular sweet mochi (mochi + sugar)!

ErinBear said...

Yes! Benkyodo in San Francisco has delicious mochi. That is where I go to get the best mochi. The blueberry mochi is actually very good. They do make ichigo daifuku, but only on weekends. I have not tried it yet because I have only been there on weekdays. I also make my own mochi at home, but I have simple tastes and generally just make it with anko filling, which is my favorite.

The peanut butter filling for mochi is surely non-traditional, but some people here seem to like it. I prefer anko or shiro-an. I also like black sesame seeds with the anko mochi. They give a good flavor.

Take care,
Erin from California

Hiroyuki said...

ErinBear: You must be exceptional! I hear a lot of non-Japanese people hate anko (sweetened bean paste)!

9895039531 seeandoh said...

I can see a lot of people love blueberries in the world from the number of comments you got on this topic. I too love blue berries. But it obviously does not grow in our tropical climate. I get only dried and salted blue berries here. Very expensive also.

Hiroyuki said...

seeandoh: Blueberries are expensive here in Japan, too. Fresh blueberries cost around 300 yen per small pack. The reason why my father consumes blueberry jam together with yogurt every morning is that he believes that blueberries are good for eyes. He has consumed blueberry jam for years, and now he need not wear his glasses although he is short-sighted.